Action  n. 1 process of doing or acting (demanded action). 2 forcefulness or energy. 3 exertion of energy or influence (action of acid on metal). 4 deed, act (not aware of his actions). 5 (the action) a series of events in a story, play, etc. B slang exciting activity (missed the action). 6 battle, fighting (killed in action). 7 a mechanism of an instrument. B style of movement of an animal or human. 8 lawsuit.  out of action not working. [latin: related to *act]