GrammarJLPT N5
→ is not
Negative Copula (is not / am not)
JLPT N5CopulaNeutral
ではない and じゃない are the negative forms of the copula だ, used to negate noun and な-adjective predicates — meaning 'is not' or 'am not.' ではない is the standard written or slightly formal form, while じゃない is its contracted, more colloquial equivalent used widely in everyday speech. Both function identically in grammar; the choice between them is purely a matter of register. In polite speech, these become ではありません or じゃありません (and the even more polite ではございません). It is important to note that ではない and じゃない are used only with nouns and な-adjectives — い-adjectives have their own negative conjugation (e.g., 高くない). Learners should be careful not to confuse じゃない used as a plain negative statement with じゃない？ spoken with rising intonation, which functions as a tag question meaning 'isn't it?'
Examples
Example #1
これは 本 ではない。
Here ではない directly negates the noun predicate 本, stating that the subject これ is not a book. This is the standard plain negative form of the copula だ. In casual conversation, this would typically be shortened to じゃない.This is not a book.
Structures
- Noun
- Noun + ではない / じゃない
- な-Adjective
- な-Adjective (stem) + ではない / じゃない
Common mistakes
A very common mistake is using ではない or じゃない with い-adjectives. For example, saying 高いじゃない is incorrect; the correct form is 高くない, since い-adjectives have their own negative conjugation and do not use the copula. Another frequent error is mixing register — using じゃない in formal writing or ではない in very casual speech, which sounds unnatural. Beginners also sometimes confuse the flat-intonation statement じゃない (meaning 'is not') with the rising-intonation question じゃない？ (meaning 'isn't it?'), which conveys the opposite meaning. Finally, learners may forget that in polite です/ます style speech, the appropriate forms are ではありません or じゃありません, not ではない or じゃない directly.
Related
ですだではありませんじゃありませんではなくではなかった