Uki Uki NihonGO! Lesson 30 – Usagi Holmes 2: Adjective Groups

Basic Fact 1:
Japanese adjectives are largely categorized into 2 groups. They are called い adjectives that end with い, and な adjectives that end with な. There are a lot more い adjectives than な adjectives in Japanese.

Basic Fact 2: い adjectives and な adjectives follow completely separate rules. So it’s important to know which group your adjective belongs to, so you can conjugate it correctly.

Present Tense: い adjective: It is hot – あついです. (simply add です)
な adjective: It is convenient – べんりです. (drop な and addです)

Negative: い adjective: It is not hot – あつくないです. (focus on く!)
な adjective: It is not convenient – ひまじゃないです. (focus on じゃ！)

Past Tense: い adjective: It was hot – あつかったです. (note かった！)
な adjective: It was convenient – べんりでした. (drop な and add でした!)

Past Negative: い adjective: It was not hot – あつくなかったです. (focus on く!)
な adjective: It was not convenient – ひまじゃなかったです. (focus on じゃ！)

Note: Some な adjectives, after you drop the な, look like an い adjective.
きれい（な）
ていねい（な）
きらい（な）
しんぱい（な）

Note 2: Some English adjectives have been incorporated into Japanese, as な adjectives.
ホットな
シャイな
ハンサムな セ
クシーな

Note 3: You can add adverbs to go along with adjectives to express varying degrees.
すごく extremely, totally
とても very
ちょっと a little bit
あまり (+ negative ending) not very…
ぜんぜん (+ negative ending) not at all…