じゃない
じゃない
expression
isn't; is not (informal); isn't it?
1.
is not; isn't (informal negative copula)
Casual contraction of ではない, the negative form of the copula だ/である. Attaches to a noun or na-adjective to express 'X is not Y'.
それは私のじゃない。
That's not mine.
彼は学生じゃない。
He isn't a student.
昨日言ったことは本当じゃないと思う。
I don't think what you said yesterday is true.
2.
isn't it?; right? (tag question)
With rising or emphatic intonation, expresses confirmation, surprise, or mild disagreement — 'isn't it!', 'don't you think?'. Similar to a tag question in English.
いいじゃない！
That's nice, isn't it!
それでいいんじゃない？
Isn't that fine the way it is?
あの店、結構美味しかったじゃない。
That restaurant was actually pretty good, wasn't it.
Casual contraction of ではない. The default informal negative copula in everyday speech.
FORMS BY POLITENESS:
- {Plain}: じゃない
- {Plain past}: じゃなかった
- {Polite}: じゃないです / じゃありません
- {Formal}: ではない / ではありません
ATTACHMENT:
- Noun + じゃない: 学生じゃない (not a student)
- Na-adjective + じゃない: 元気じゃない (not well)
- Cannot attach directly to i-adjectives or verbs — those have their own ない negatives (高くない, 行かない).
SENSE 2 — TAG QUESTION:
With rising or emphatic intonation, じゃない seeks agreement or expresses mild surprise. Often follows the explanatory ん: いいんじゃない？ ('isn't that okay?'). Without the question mark, the same construction can express positive evaluation: いいじゃない！ ('that's great, isn't it!').
SIMILAR WORDS:
- ではない: more formal written form
- じゃありません: polite negative
- じゃん: even more casual confirmation tag (Kanto dialect, now widespread)