coward

腰抜け(こしぬけ)	Someone who becomes paralyzed when the shit goes down. Someone who is too frightened to react.

意気地なし(いくじなし)	Someone who is a coward – not just that they run from a fight, but they run to tell their Mom and ask her to kick your ass.

卑怯な(ひきょうな)	To do something both cowardly and mean – to hit below the belt.