'Zhāi mào zi' literally means 'to take off a hat', but it is an idiom used figuratively to mean removing an unfair, negative label or stigma that has been imposed on someone or something — such as political accusations, social stereotypes, or moral judgments. The 'hat' (mào zi) symbolizes the label itself, often one assigned arbitrarily or unjustly; 'zhāi' (to remove) conveys the act of rejecting or lifting that designation.

This expression originated in mid-20th-century Chinese political discourse, where assigning ideological 'hats' (e.g., 'rightist', 'counter-revolutionary') was common. Today, it’s widely used in media, law, education, and everyday speech to describe efforts at rehabilitation, exoneration, or social reintegration — for example, clearing someone’s name after false allegations or revising outdated societal views about a group.