The term 'Jump the ___' can be completed with two different answers: 'GUN' (3 letters) and 'SHARK' (5 letters). Jumping the GUN is an idiom that means to do something too soon or without proper preparation. It is often used in the context of making a decision or taking action before all the facts are known. Jumping the SHARK is a phrase that refers to a moment when something that was once popular has become ridiculous or over-the-top. It originated from a scene in the TV show Happy Days where the character Fonzie jumped over a SHARK while on water skis.