Verbal jabs are a form of communication that involve insulting or mocking someone. They are often used in an attempt to hurt the other person's feelings or to gain an advantage in an argument. The term 'FLAK' is a slang term for verbal jabs, and it is derived from the German word for anti-aircraft fire. FLAK is used to describe the barrage of criticism or insults that someone may receive when they are in a vulnerable position.