From Longman Dictionary of Contemporary Englishwhat do you mean ...?what do you mean ...?a) UNDERSTANDused when you do not understand what someone is trying to say ‘You’ll be careful won’t you?’ ‘What do you mean?’ b) SURPRISEDused when you are very surprised or annoyed by what someone has just said What do you mean, you’ve cancelled the trip? What do you mean by that? c) used when you are very annoyed by what someone has just done What do you mean by calling me at this time of night? → mean
