Translation guide
The English phrase "are not" is the negative form of "are," used to negate states, identities, or actions. In Japanese, negation is expressed through verb/adjective conjugation or the copula, not a separate word. The translation depends entirely on what is being negated.
To say that something is not something else, or does not have a certain property (for na-adjectives).
The standard negative form of the copula だ. Used in plain/informal speech. For polite speech, use ではありません.
The polite negative form of the copula です. Used in formal situations or with strangers.
これは私の本ではありません。
This is not my book.
A contracted, more casual form of ではない. Very common in spoken Japanese.
それ、猫じゃないよ。
That's not a cat.
A slightly less formal polite negative, often used in speech. Equivalent to ではありません.
これは私のじゃありません。
This is not mine.
To say that something does not have a certain quality described by an i-adjective.
Replace the final い of an i-adjective with くない to make it negative in plain form. For polite form, add です: 〜くないです.
この料理は美味しくない。
This food is not delicious.
今日は寒くないです。
It is not cold today.
The formal negative form of i-adjectives. Less common in speech, but used in formal writing.
この部屋は広くありません。
This room is not spacious.
To say that someone or something is not currently doing something or is not in a certain state (equivalent to 'is not -ing').
The negative of the ている form. For verbs, it means 'is not doing' or 'has not done' (resultant state). Plain form.
彼はまだ来ていない。
He has not come yet. / He is not here yet.
私は何も食べていない。
I haven't eaten anything.
Polite negative of ている. Used in formal contexts.
まだ決めていません。
I haven't decided yet.
To say that something does not exist or is not present.
Negative of いる, used for animate things (people, animals). Plain form.
部屋に誰もいない。
There is no one in the room.
Polite negative of いる.
先生はいません。
The teacher is not here.
Negative of ある, used for inanimate things and abstract concepts. Plain form.
お金がない。
I have no money. (lit. Money does not exist.)
Polite negative of ある.
質問はありません。
I have no questions. (lit. Questions do not exist.)
English uses 'are not' as a separate auxiliary verb, but Japanese negation is built into the predicate. There is no single Japanese word for 'are not.' Always identify what is being negated (noun, adjective, verb) and use the appropriate negative form.
彼らは学生ではない。
They are not students.
ではない is the standard plain negative copula, while じゃない is a contraction used in casual speech. In formal writing or polite conversation, use ではありません or じゃありません. じゃない can sound abrupt if used in formal settings.