形容詞の変化

There are two classes of Japanese adjectives referred to in this document as い-adjectives and な-adjectives. い-adjectives are actually a special class of verb and therefore require no predicate.  They do however require conjugation.  な-adjectives, also called copular nouns, are actually nouns and need no conjugation, but do require a predicate in order to activate their adjectival function.

The Conjugations

い-adjectives
In the following chart showing the conjugation of the い-adjective 寒い [samui, cold] notice that when い-adjectives are informal they require no predicate. You will never see an い-adjective followed by だ. However to make い-adjectives polite you would add です.  

Informal (Common 普段)
寒い	Present Affirmative	is/are cold
寒くない	Present Negative	is not/are not cold
寒かった	Past Affirmative	was/were cold
寒くなかった	Past Negative	was not/were not cold
寒かろう	Tentative	is/are probably cold

 

Formal (Polite 丁寧)
寒いです	Present Affirmative	is/are cold
寒くないです	Present Negative	is not/are not cold
寒かったです	Past Affirmative	was/were cold
寒くなかったです	Past Negative	was not/were not cold
寒いでしょう	Tentative	is/are probably cold

 

Conditional and Conjunctive
寒ければ	Conditional	if [subject] is/was cold
寒くなければ	Negative Conditional	if [subject] is not/was not cold
寒くて	Conjunctive	is/are cold ... and/so
寒くなくて	Negative Conjunctive	is not/are not cold ... and/so

 
Keep in mind though that です would only be used when the い-adjective is at the end of a sentence and only to make it polite.  This is because い-adjectives are a special type of verb so even without だ/です the meaning of 寒い is "is cold" and not just "cold."  If an い-adjective is used to modify something in the middle of a sentence, you would use no predicate regardless of the level of politeness.  Here are some examples to clarify this point:

Informal	Polite
寒い天気だ。 [samui tenki da.] It's cold weather. (adjective in the middle)	寒い天気です。 [samui tenki desu.] It's cold weather. (adjective in the middle)
お天気は寒い。 [otenki wa samui.] The weather is cold. (adjective at the end)	お天気は寒いです。 [otenki wa samui desu.] The weather is cold. (adjective at the end)

There is one irregular case, which is いい/よい [ii/yoi, good].  With this い-adjective you would use いい or よい for present affirmative but use only よい for conjugating all other tenses like so:

Informal (Common 普段)
いい	Present Affirmative	is/are good
よくない	Present Negative	is not/are not good
よかった	Past Affirmative	was/were good
よくなかった	Past Negative	was not/were not good
よかろう	Tentative	is/are probably good

 

Formal (Polite 丁寧)
いいです	Present Affirmative	is/are good
よくないです	Present Negative	is not/are not good
よかったです	Past Affirmative	was/were good
よくなかったです	Past Negative	was not/were not good
よいでしょう	Tentative	is/are probably good

 

Conditional and Conjunctive
よければ	Conditional	if [subject] is/was good
よくなければ	Negative Conditional	if [subject] is not/was not good
よくて	Conjunctive	is/are good ... and/so
よくなくて	Negative Conjunctive	is not/are not good ... and/so

な-adjectives
In this next chart showing the conjugation of the な-adjective 綺麗な [kireina, pretty] notice that unlike い-adjectives, when な-adjectives are informal and at the end of the sentence they are followed by だ.  な-adjectives must always be followed by a predicate or by -な.  

Informal (Common 普段)
綺麗だ	Present Affirmative	is/are pretty
綺麗ではない	Present Negative	is not/are not pretty
綺麗だった	Past Affirmative	was/were pretty
綺麗ではなかった	Past Negative	was not/were not pretty
綺麗だろう	Tentative	is/are probably pretty

 

Formal (Polite 丁寧)
綺麗です	Present Affirmative	is/are pretty
綺麗ではありません	Present Negative	is not/are not pretty
綺麗でした	Past Affirmative	was/were pretty
綺麗ではありませんでした	Past Negative	was not/were not pretty
綺麗でしょう	Tentative	is/are probably pretty

 

Conditional and Conjunctive
綺麗だったら	Conditional	if [subject] is/was pretty
綺麗ではなかったら	Negative Conditional	if [subject] is not/was not pretty
綺麗で	Conjunctive	is/are pretty ... and/so
綺麗ではなくて	Negative Conjunctive	is not/are not pretty ... and/so

Like い-adjective だ/です would only be used when a な-adjective is at the end of a sentence but this time they are required because な-adjectives are a type of noun so だ/です is used to make the meaning of 綺麗 into "is pretty" and not just "pretty."  If a な-adjective is used to modify something in the middle of a sentence, you would use the な-adjective root followed by -な. Here are some examples:

Informal	Polite
佐藤さんは綺麗な人だ。 [satousan wa kireina hito da.] Mrs. Sato is a pretty person. (adj. in the middle)	佐藤さんは綺麗な人です。 [satousan wa kireina hito desu.] Mrs. Sato is a pretty person. (adj. in the middle)
佐藤さんは綺麗だ。 [satousan wa kirei da.] Mrs. Sato is pretty. (adjective at the end)	佐藤さんは綺麗です。。 [satousan wa kirei desu.] Mrs. Sato is pretty. (adjective at the end)

Some Practice Adjectives

Here is a list of adjectives that you can use to practice the conjugations we have gone over thus far.  Pay particular attention to the differences in the usage of だ/です with い-adjectives and な-adjectives.  Also note how both types of adjectives differ when used in the middle of a sentence or at the end of the sentence.  It might be beneficial to learn the conjugations by drilling them first, then practice using them in sentences, writing them down on paper and saying them out loud.

い-adjectives
暖かい	あたたかい	warm
熱い	あつい	hot
痛い	いたい	painful
美しい	うつくしい	beautiful
固い	かたい	hard (vs. soft)
厳しい	きびしい	harsh
素晴らしい	すばらしい	wonderful
鋭い	するどい	sharp
高い	たかい	tall, high
正しい	ただしい	right, proper
長い	ながい	long
低い	ひくい	short (stature)
短い	みじかい	short (length)
難しい	むずかしい	difficult
優しい	やさしい	easy
安い	やすい	cheap, inexpensive
柔らかい	やわらかい	soft

な-adjectives
鮮やかな	あざやかな	fresh
哀れな	あわれな	pitiful, wretched
異常な	いじょうな	abnormal
意地悪な	いじわるな	mean
嫌な	いやな	distasteful
頑固な	がんこな	stubborn
簡単な	かんたんな	easy
静かな	しずかな	quiet
好きな	すきな	likeable, favorite
丁寧な	ていねいな	polite
生意気な	なまいきな	conceited, impudent
派手な	はでな	showy, cheeky
不思議な	ふしぎな	mysterious
不便な	ふべんな	inconvenient
変な	へんな	strange
便利な	べんりな	convenient
真面目な	まじめな	serious
野蛮な	やばんな	savage, barbarous

After each conjugation you write stop and think about how you would use it in a sentence.  Try to relate each conjugation to the essence of their English equivalent.  After some time, the nuance of time, negativity and the level of politeness conveyed by these adjective endings will become second nature to you and you will be able to drop the use of English equivalents (of course finding English equivalents for levels of politeness is a little difficult since 熱い and 熱いです both mean it's hot in English.  The level of politeness to use can only be felt out through observing what levels of politeness Japanese people themselves use in different situations.  However a good rule of thumb is to use informal with family and friends, and polite with strangers and in formal situations).

ホーム  平仮名と片仮名  日本語の名詞  日本語の助詞  だ/です

ある/ いる  形容詞の変化  動詞の変化  漢字辞典  日本語クイズ

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