The term 'Battle Stopper' refers to a situation in which a conflict is ended or prevented by a TRUCE or PACT. A TRUCE is an agreement between two sides to stop fighting, usually for a limited period of time, and a PACT is a formal agreement between two or more parties. In this case, the crossword solutions for the term 'Battle Stopper' are 'TRUCE' (5 letters) and 'PACT' (4 letters). Both terms refer to agreements that can be used to end or prevent a battle.