expression, i-adjective
sharp-tongued; sarcastic; foul-mouthed
Describes a person whose way of speaking is harsh, cutting, or unkind. Often used for someone who habitually makes biting remarks.
See also: 口の悪い
彼は口が悪いけど、本当は優しい人だ。
He has a sharp tongue, but he's actually a kind person.
あの人は口が悪いから、気をつけたほうがいいよ。
That person is sarcastic, so you'd better be careful.