'Tarty' describes a woman's clothes, make-up, or look as being cheap and sexually available — too much, too tight, too bright, in a way the speaker disapproves of. It is British and Irish, informal, and it is an insult. You should understand this word rather than use it. Two things matter here. First, it is a judgement about respectability, not a description of a fact — 'tarty' means the speaker thinks a woman looks like she is trying too hard to attract men, and different speakers draw that line in wildly different places. Second, it is one-sided: there is no real male equivalent in ordinary use, which tells you what the word is doing. It comes from 'tart', an old slang word for a prostitute (which itself came, oddly, from 'sweetheart' — the affectionate use came first and soured). Because of that history, calling a woman's outfit tarty is not a light comment; it can land as a serious insult about her character. Younger British speakers now often use it half-jokingly about their own clothes ('these shoes are a bit tarty, aren't they?'), and among close friends that self-mocking use is fairly common. But directed at someone else, it is rude. As a learner, know it when you hear it in a film or a novel, and choose another word yourself.

（貶）穿得很騷、打扮很俗艷、看起來輕浮的（用來說女生）。英式口語，是罵人的話，不是中性描述。台灣說「很騷」「很花枝」大概是這個力道。建議只要看懂就好，自己不要用。