The answer to the crossword puzzle is 'FISTS, ' which is an acronym for 'Feet In Street Tactics, ' a form of self-defense. FISTS is a martial art that focuses on using the feet and FISTS to defend oneself from attackers. It is a combination of boxing, kickboxing, and other martial arts techniques. The term 'they may be pumped or bumped' refers to the use of punches and kicks in FISTS, which can be used to either pump up the attacker or bump them away.