From Longman Dictionary of Contemporary Englishtit for tatˌtit for ˈtat noun [uncountable] informalATTACK something bad that you do to someone because they have done something bad to youOrigin tit for tat (1500-1600) Probably from tip for tap “tit for tat” ((1500-1600)), from tip “light blow” ( → TIP1) and tap “light blow”
