Adjectival Nouns I 形容動詞①
Apart from true adjectives (形容詞), words known as “adjectival nouns” also constitute attributes in Japanese. Though all such words must use the copula verb to be used adjectivally, many can also function as true norms; however, the degree to which these words may be used as nouns varies. To get a sense of how words may differ by the degree of how “noun-like” they are, consider the following scenarios.
■Situation 1: Seldom Noun-like~Purely Adjectival
The first word, 簡単, means “simple/easy,” but because it cannot conjugate on its own, its predicative form (終止形) is 簡単だ. For adjectival nouns, the attributive form (連体形) is not identical to the predicative form (終止形). When placed before a noun, ～だ changes to ～な. Why these forms look different for adjectival nouns but not for adjectives is the result of sound changes over time.
i. その説明は簡単だ。（終止形）
That explanation is simple.
ii. 簡単な説明だ。（連体形）
(It’s) a simple explanation.
簡単 heavily leans toward being used as an adjective. Dictionaries do list it as potentially being a noun, but such contexts are always special.
iii. 簡単が一番！(Nominal)
‘Easy’ is the best!
■Situation 2: Completely Dual-Natured as Either Noun or ‘Adjective’
Next, consider the word バカ, which means “idiot/stupid.” In English, “idiot” is a noun and “stupid” is an adjective. Simply put, in Japanese it is both a noun and an adjectival noun.
iii. 山田君は、バカだね。(Nominal or Adjectival)
Yamada-kun, you’re sure an idiot.
Yamada-kun sure is stupid, huh.
Although we will still be going over the non-past, past, and negative forms, because we have already technically learned how to conjugate them when we learned about the copula, this lesson will primarily focus on grammar. With that being said, let’s review the grammar terms we will need for this discussion!
- Predicate: The part of a sentence that makes a statement about the subject.
- Auxiliary: An ending that helps construct verbal conjugations.
- Adjective: A word that describes an attribute.
- Adjectival Noun: A word that describes an attribute while also being noun-like.
- Base: One of the six forms that a conjugable part of speech (verb, adjective, auxiliary verb, etc.) may take which is then followed by endings (auxiliaries, etc.).
- Terminal/Predicative Form: Known in Japanese as the 終止形, it marks the end of a complete sentence/the predicate.
- Attributive Form: Known in Japanese as the 連体形, it is used to make a verb, adjective, etc. into a modifier that goes directly before a noun.
- Basic Form: The basic form of any given phrase utilized in plain speech as well as in many grammatical circumstances. The basic form in the context of adjectival nouns specifically refers to the attributive form because the adjectival nature of these words is indisputable when placed before a noun.
- Continuative Form: Known in Japanese as the 連用形, it is used with endings pertaining to actions being carried out.
Terminology Note: The Japanese term 形容動詞 literally translates to “adjectival verb,” viewing the copula verb as a helper verb. Although the term “na-type adjectives” (ナ形容詞) is commonly used instead, 形容動詞 will be used as this is how Japanese speakers refer to them.
The Non-Past Forms (Plain/Polite)
非過去形（常体・丁寧体）
Adjectival nouns are not typically interpreted as being in the future tense without additional grammar/context. Aside from this point, everything for the non-past tense has been showcased already, but the chart below summarizes this with examples.
| Meaning | Basic/Attributive Form （＋～な） | Predicative Form （＋～だ） | Predicative Form (Polite) （＋ ～です） |
| Safe | 安全（な） | 安全だ | 安全です |
| Healthy | 健康（な） | 健康だ | 健康です |
| Lively/Well | 元気（な） | 元気だ | 元気です |
| Convenient | 便利（な） | 便利だ | 便利です |
| Inconvenient | 不便（な） | 不便だ | 不便です |
Spelling Note: A hyphen is placed in between the adjectival noun and the copula to indicate that they are joined. When a word is used as a noun before the copula, no hyphen will be used. This will hold true for any conjugation.
Vocabulary Notes:
①安全 may also be used as a noun to mean “safety.”
②健康 may also be used as a noun meaning “(physical) health.”
In the examples below, the adjectival noun will be marked with either “adjectival” or “nominal” to indicate how it functions in the sentence.
1. 病院は安全です。(Adjectival)
The hospital is safe./Hospitals are safe.
2. 安全第一！(Nominal)
Safety First!
3. チェコ語は簡単だ。(Adjectival)
Czech is easy.
4. （私たちの）健康は大切です。(Nominal)
(Our) health is important.
5. 元気な子供ですね。(Adjectival)
The child/children are sure full of energy, huh.
6. 私の歯は健康です。(Adjectival)
My teeth are healthy.
7. 毎日の生活で不便なことは何ですか。(Adjectival)
What are inconvenient things in your everyday life?
Grammar Notes:
①The particle か marks a question.
②Even though もの means “thing,” when the “thing” is not a physical object, こと is used instead.
8. ここは便利な店ですね。(Adjectival)
This sure is a convenient store.
Phrasing Note: “Convenience store” is コンビニ, a shortening of コンビニエンスストア. This may come as a surprise to Chinese speakers as 便利店 is their word for “convenience store.” Interestingly, the phrase 便利屋 does exist in Japanese, but it refers to a “Jack of all trades.”
Dropping the Copula
When an adjectival noun is in the predicative form and the copula is dropped, the resulting tone of the sentence is exclamatory.
9. おお、見事（だ）！
Oh, how splendid!
10. 僕は元気！
I’m great!
The Existence of Two Attributive Forms: ～な vs ～である
Japanese allows entire sentences to modify a noun so long as the modifier is to the left of what it modifies, and so long as the speaker applies the correct grammatical glue – the “attributive form.” Both nouns and adjectival nouns may end an attributive clause which modifies a noun, but whether the copula manifests as ～な or ～ある will differ between the two.
Scenario 1: “Regular” Nominal-Predicate + Regular Noun: である 〇
When a regular noun modifies another noun, as opposed to an adjectival noun, you cannot use ～な to link them together, whether the noun constitutes a predicate or not.
In Lesson 9, we learned how だ is a contraction. Unravel だ, and you get である (predicative/attributive form). This uncontracted form lets you link nouns together much like the particle の, but it is the go-to option when a whole predicate which happens to end in a noun is modifying a noun.
11. 男【である 〇・だ 〇】。
(I/the person) is/am a man.
12. 自民党の誰々が総理大臣である限り、何も変わらない。
As long as so-and-so in the LDP is the Prime Minister, nothing will change.
The nominal (noun) phrase before である is an entire clause: [自民党の誰々が総理大]. The second noun is 限り meaning “limit/extent.” In this context, it translates like an adverb as “as long as.”
13. 性自認が男【である 〇・ だ X・な △】人。
A person who(se gender identity) is male.
Scenario 2: Regular Noun + Regular Noun: The Particle No の
As established, ～な is not used between two regular nouns. To join two nouns in an attributive relationship when the first does not constitute a predicate, you use the particle の (Ex. 14). ～である, on the other hand, is appropriate when the nominal phrase is a nominal predicate (Ex. 13).
14. 男【な X ・の 〇・である X】人です。
The person is a man.
Nuance Note: 男の人 is the politer way to say 男.
Scenario 3: Adjectival-Noun Predicate + Noun: ～である
Adjectival-noun predicates may use ～である both in attributes (Ex. 16) and as the main predicate (Ex. 15).
15. この地域は安全である。(Formal)
This area is safe.
16. データが安全[である 〇・な X]ことを確認する。
To confirm that the data is safe.
Scenario 4: Adjectival Noun + Noun: ～な
When an adjectival noun modifies a noun but is not part of a predicate, ～な is the appropriate attributive form of the copula.
17. 安全なデータ
Safe data
18. データが[安全な状態]にある。
The data is in a safe state.
In Ex. 18, データ is actually the subject of the sentence and is NOT embedded in a modifier clause. Therefore, ～な is the correct attributive form. However, consider the following.
19. 安全な状態
A safe state
20. 安全である状態
The condition of being safe
If you interpret the adjectival noun as constituting a predicate, you get Ex. 20. If you do not, you get Ex. 19.
Scenario 5: Nominal/Adjectival-Noun Predicate + Noun: ～な?
Though quite convolutedly, in the spoken language and informal writing, ～な does often replace ～である in noun-modifying attributes. The reason for this is thought to lie in how ～である sounds old-fashioned despite being grammatically necessary at times.
21. データが安全でないことが原因【な △・である 〇】場合がある。
There are cases in which the cause is that the data is not safe.
[データが安全でないことが原因] is a clause within a clause. こと is a noun which in this sentence enables the preceding predicate to be used as a noun.
In Ex. 12, ～である is essentially holding together a rather complicated adverbial phrase. In Ex. 16, the であること phrase is the object of the sentence. These specific grammatical contexts are thought to block ～である from being replaced by ～な in casual speech.
In Ex. 21, [データが安全でないことが原因【な △・である 〇】場合] is the subject of the main clause of the sentence, and the overall sentence structure is still just a basic existential sentence, whereas neither Ex. 11 nor Ex. 16 are existential in nature. This is believed to be the grammatical prerequisite for overlap between ～な and ～である in predicative attributes. Now, as for Ex. 13, this is why ～な is marked as △.
Speech Register Note: In mid-sentence, ～である is occasionally grammatically necessary as we have found. At the end of a sentence (predicative form), it may give off either a formal, literary tone or a very pedantic tone if used in the spoken language.
The Past Tense Forms (Plain/Polite)
過去形（常体・丁寧体）
We’ve learned previously that the past tense forms of the copula are だった (plain) and でした (respectively). In each case, the past tense marker ～た follows the continuative form – “d(e)ari-” and “deshi-” respectively prior to conjugating.
As we have learned, だった can be used to directly modify nouns, but でした cannot because です forms lack an attributive form.
If you are still wondering why plain forms such as だった can modify nouns, remember that all endings in plain speech possess a predicative form and an attributive form. Japanese has to have a means to allow for complex modifiers to attach a noun, and the attributive form is that glue.
22. 綺麗[だった 〇・でした X] あたし
My once pretty self
23a. 食糧の確保が必要であった時代 (Formal, written language)
23b. 食料の確保が必要だった時代 (Written or Spoken)
23c. 食料の確保が必要でした時代 Ｘ (Incorrect)
Time period when the guarantee of a food supply was important
24. 簡単だった試験
Kantan-datta shiken
(A/the) exam that was easy
Exs. 22-24 show three deeply rooted differences in grammar between English and Japanese that can’t be overlooked.
- The past tense isn’t expressed by the affix “-ed” in English in either example, but the adjectives in Japanese ARE directly conjugated into the past tense.
- Whereas the conjugated adjective directly modifies the following noun to the left of it thanks to the attributive form, English requires that a helper word like “when” go in between the noun and the modifying clause and that the modifying clause go to the right of the noun. The word order is completely opposite.
- The use of “self” over “I” is a matter of English pronoun use whereas Japanese pronouns are regular nouns that can be modified no differently than any other noun.
Now that we have hashed out these grammar concerns, let’s look at some more adjectival nouns conjugated into the past tense in both plain and polite speech.
| Meaning | Basic Form | Predicative/Attributive ＋～だった | Predicative Form Only ＋～でした |
| Pretty/Clean | 綺麗（な） | 綺麗だった | 綺麗でした |
| Necessary | 必要（な） | 必要だった | 必要でした |
| Important | 大切（な） | 大切だった | 大切でした |
| Essential | 重要（な） | 重要だった | 重要でした |
| Crucial/Precious | 大事（な） | 大事だった | 大事でした |
| Rude | 失礼（な） | 失礼だった | 失礼でした |
| Fresh | 新鮮（な） | 新鮮だった | 新鮮でした |
Vocabulary Notes:
①大切, 重要, and 大事 can all translate as “important,” but they are not exactly the same.
・大切 refers to something that is important in the sense that if the thing in question were lost, there would be harm felt on an emotional level.
・重要 refers to objective importance.
・大事 refers to things/people you take special care to. Or, it may be used as a noun meaning “serious matter/crisis.”
25. 月は綺麗でした。
The moon was pretty.
26. 大切だった人
A person who was indispensable/important
27. 英語能力が重要でした。
English proficiency was important.
28. まさに大事だった。
It was a serious matter, exactly.
The Negative Forms (Plain/Polite)
否定形（常体・丁寧体）
Because we have already learned how the copula is conjugated, we will not be revisiting how each possible negative form is made. Instead, the chart below lists the possible forms from least to most polite. Just remember the general observation that contractions are less formal.
| Meaning | Basic Form (Attributive) | Negative Forms (Least to Most Polite) |
| Strange | 変（な） | 変じゃない 変ではない 変じゃないです 変ではないです 変じゃありません 変ではありません |
| Excellent | 優秀（な） | 優秀じゃない 優秀ではない 優秀じゃないです 優秀ではないです 優秀じゃありません 優秀ではありません |
| Enough | 十分（な） | 十分じゃない 十分ではない 十分じゃないです 十分ではないです 十分じゃありません 十分ではありません |
| Real | 本当（な） | 本当じゃない 本当ではない 本当じゃないです 本当ではないです 本当じゃありません 本当ではありません |
| Complicated | 複雑（な） | 複雑じゃない 複雑ではない 複雑じゃないです 複雑ではないです 複雑じゃありません 複雑ではありません |
Vocabulary Notes:
①優秀 refers to someone’s skill(s) being exceptional.
②本当 can also mean “really” and may be used as a noun, adjective, or an adverb. It can also translate as “true” or “genuine.”
29. この気持ちは変じゃない。
This/these feeling(s) is/are not strange.
30. あれはもはや重要ではない。
That is no longer important.
31. あの人は優秀じゃありません。
That person isn’t excellent/superb.
The Negative-Past Forms (Plain/Polite)
過去の否定形（常体・丁寧体）
Because the plain and polite negative-past forms of adjectival nouns utilize the copula, we will forgo an etymological breakdown. Instead, the recap chart below will list variations from least to most polite. We will also forgo discussing why the polite forms can’t be used as attributes as the reasoning is the same as before.
| Meaning | Basic/Attributive Form | Negative-Past Forms (Least to Most Polite) |
| Dangerous | 危険（な） | 危険じゃなかった 危険ではなかった 危険じゃなかったです 危険ではなかったです 危険じゃありませんでした 危険ではありませんでした |
| Appropriate | 適切（な） | 適切じゃなかった 適切ではなかった 適切じゃなかったです 適切ではなかったです 適切じゃありませんでした 適切ではありませんでした |
Vocabulary Note:
①危険 is synonymous with 危ない, but the latter has a wider range of use.
32. 野菜は新鮮じゃありませんでした。
The vegetables weren’t fresh.
33. 全然失礼じゃなかったですよ。
(He/she/you/that) wasn’t rude at all.
34. 記述は複雑じゃなかった。
The description wasn’t complicated.
35. それは適切ではなかった。
That was not appropriate.
36. あの町は危険じゃなかった。
That town wasn’t dangerous.
Native Adjectival Nouns
和語系の形容動詞
Some educators erroneously state that all adjectival nouns arose due to Chinese influence. Although it is true that most are Sino-Japanese in origin, native adjectival nouns have always existed.
Sometimes, an adjectival-noun form is made by dropping /i/ and just using the stem, but most are made by following the stem with the suffixes ～か, ～らか, or ～やか. The difference in nuance is usually that the adjectival noun form(s) are more abstract, intangible, and/or refined.
| Meaning | Root | Adjective | Adjectival Noun （＋～か・らか・やか） |
| New | Ara– | 新しい | 新ただ △ |
| Quiet | Shizu– | 静かだ | |
| Soft | Yawa– | 柔らかい | 柔らかだ △ |
| Fine/small | Koma– | 細かい | 細かだ △ 細やかだ |
| Flat | Tai- | 平らだ | |
| Small | Chiisa– | Chiisai 小さい | 小さな |
| Big | Ō– | 大きい | 大きな |
Grammar Note: Some of these words are unnatural in the predicative form .
①As for 新しい vs 新ただ, the latter is essentially non-existent. Conversely, the attributive form 新たな is frequently used, but it has a romanticized undertone that 新しい does not.
②The ～な in 小さな and 大きな is thought to be completely fused to these roots and, thus, cannot conjugate.
37. 新たな冒険がいま、始まります！
A new adventure starts now!
38. あの図書館は静かです。
That library is quiet.
39. 柔らかな風が吹く。
Gentle wind blows.
40. 柔らかい布を使う。
To use soft cloth.
41. 皆さん、大きな拍手をお願いします。
Everyone, please give a big round of applause.
42. 平らな石が二つありました。
There were two flat stones.
Of course, there are other native adjectival nouns that are not created with these suffixes. As for the rest, the only way to distinguish them from nouns is by verifying their semantic role if used in the predicative form. When used in the attributive form the presence of ～な alone would indicate their adjectival nature.
| Meaning | Basic/Attributive Form | Meaning | Basic/Attributive Form |
| Rare | 稀（な） | Various | 色々（な） |
| Obvious | 当たり前（な） | Unpleasant | 嫌（な） |
| Pitiful | 哀れ（な） | Dirty (sexually) | エッチ（な） |
Vocabulary Notes:
①当たり前 comes from a misspelling of 当然. The two words are interchangeable.
②The word エッチ, often simply spelled as Ｈ, comes from the “H” in the romanized spelling of 変態, an all too familiar word to many because of its meaning of “pervert.”
43. トレーニングが必要なことも稀ではありません。
It is also not rare for training to be necessary.
44. 当たり前が当たり前じゃなかったことに気づいた。
I realized that what was/the “obvious” wasn’t obvious.
Grammar Note: In this sentence, 当たり前’s dual nature as either a noun or adjectival noun is on full display. The use of こと to make the preceding phrase a noun also highlights how any basic plain speech conjugation (past, negative, negative-past) can modify a noun in return.
Foreign Adjectival Nouns
外来系の形容動詞
A small handful of adjectival nouns come from loanwords. Sometimes, their meanings will be different from what they were in the original language. Some may even be used without –na な at all if part of a phrase borrowed verbatim.
| Meaning | Basic/Attributive Form | Meaning | Basic/Attributive Form |
| Modern | モダン（な） | Handsome | ハンサム（な） |
| Realistic | リアル（な） | Chic | シック（な） |
| Smart/Slender/Stylish | スマート（な） | Formal | フォーマル（な） |
45. リアルなゲームが好きです。
I like realistic games.
46. シンプルなデザインのメリット
The merit(s) of a simple design
47. スマートな身なり
Stylish attire
48. スマートな体型の男性
A man with a slim build
Exception Note: A slang word which entered in the 1980s involved turning the English word now into a 形容詞 – ナウい (trendy). It is one of a kind morphologically, but it has since fallen out of use.
In Conclusion… 最後に…
Perhaps the most daunting task of all is that the “na-adjectival nouns” you just learned about are not the only kind of adjectival nouns (→ no-adjectival nouns).