expression, auxiliary
Colloquial negative form of そうだ, used after adjectives, nouns, and verbs to express 'it doesn't look like' or 'it doesn't seem'. The じゃ is a contraction of では, making it informal. Often used in casual speech.
See also: では無さそう (ではなさそう)
この料理、辛いんじゃなさそう。
This dish does not seem to be spicy.
彼は来るんじゃなさそうだね。
It does not seem like he is coming.