knock it off exclamation 1verb 1forms 3 exclamation1 •Cease doing something, particularly annoying or unpleasant; desist.Knock it off! This is the last time I'm telling you! verb1 •(informal) To cease doing something, particularly annoying or unpleasant; to desist.Would you two please knock it off with the shouting? I'm trying to sleep. formsknocked it off · knocking it off · knocks it off