SARCASM

[noun] [U] - (the use of) remarks which clearly mean the opposite of what they say, and which are made in order to hurt someone's feelings or to criticize something in an amusing way"You have been working hard", he said with heavy/biting sarcasm, as he looked at the empty page.Compare irony (FIGURATIVE SPEECH).(saying) 'Sarcasm is the lowest form of wit' means that sarcasm is the most unkind type of humour.