From Longman Dictionary of Contemporary Englishsomebody/something is not all thatsomebody/something is not all thatused to say that someone or something is not very attractive or desirable I don’t know why you keep chasing her around. She’s not all that. → all
Examples from the Corpus
somebody/something is not all that• I don't know why you keep chasing her around - she's not all that.• The woe that is in marriage is not all that bad really.• But language is not all that conventional and matter of fact.• Issue 100 is not all that far away.• But the ordinary ground of palpable reality and time-bound day-to-day existence is not all that firm anyhow.• Obviously enough, action is not all that is required for thought.• As you probably know, even the cleanest looking carpet is not all that it appears.• The geographical context is not all that matters, but it is the most significant.• The little secret no one lets out is that what one does after putting on the badge is not all that exciting. 