The term 'STOP THAT!' can be expressed in a variety of ways, as demonstrated by the crossword solutions IXNAY (5 letters), ENOUGH (6 letters), DONT (4 letters), COOLIT (6 letters), QUITIT (6 letters), and CUTITOUT (8 letters). IXNAY is a slang term derived from the phrase 'nix it, ' which means to reject or forbid something. ENOUGH is a word used to indicate that a certain amount or degree has been reached. DONT is a contraction of the phrase 'do not.' COOLIT is a slang term meaning to calm down or relax. QUITIT is a slang term meaning to stop doing something. CUTITOUT is a slang term meaning to stop doing something immediately.