Grammar - Beginner - Part 4
nai ない
Adjective used as the negative of the verb aru/da, or for making the negative form of verb or adjective.

It conjugates as an adjective.
ta-form: nakatta (plain) / nakatta desu (polite)
te-form: naide (after verb) / nakute (after adjective or after verb when expressing a cause for some emotion)

1. Used as negative of aru

ここに置いてあったかばんがない。
Koko ni oite atta kaban ga nai.
The bag I left sitting here is missing.

遊ぶ時間がなくて不満だ。
Asobu jikan ga nakute fuman da.
I am discontented because I have no time to play.

2. Used as negative of da

これは日本製の車ではない。
Kore wa nihonsei no kuruma dewa nai.
This is not a Japanese-made car.
(dewa must be used between ''adjectival'' noun and nai)

3. Used to make nai-form of verb

(added to the stem of verb)
今パスポートを持っていない。
Ima pasupouto o motte inai.
I don't have my passport now.

もう電車に間に合わない。
Mou densha ni ma-ni-awanai.
It's already too late to make the train.

4. Used in te-form

ここでタバコは吸わないでほしい。
Koko de tabako wa suwaide hoshii.
I want you not smoke here. (I don't want you to smoke here.)

努力しないで成功はしません。
Doryoku shinaide seikou wa shimasen.
You won't succeed without making efforts.

彼はお礼も言わないで帰ってしまった。
Kare wa o-rei mo iwanaide kaette shimatta.
He went home without expressing thanks.

彼女は来られなくて残念です。
Kanojo wa korarenakute zannen desu.
It is a pity that she cannot come.

5. After ku-form of adjective

このカメラは思ったほど高くはなかった。
Kono kamera wa omotta hodo takaku wa nakatta.
This camera was not as expensive as I had expected.
(wa or mo used between ku-form and nai adds emphasis)

-> See also: aru, arimasen, desu, masu, zu ni, Verb Forms (2)