act

act, action

1. The distinction between the two words in their general meanings is not always clear: we are judged by our acts or by our actions. In general, however, action has more of the notion of performance, and extends to inanimate things (we can speak only of the action, not of the act, of a machine), whereas act connotes more strongly the fact of something done and also implies responsibility rather more necessarily than action does (hence the Acts of the Apostles, not the Actions, which Fowler (1926) suggested as the logical preference). Action is also used attributively in expressions such as action committee, painting, replay, etc., whereas act is not. The actions of a person are usually viewed as occupying some time, and (in the plural) denote the habitual or ordinary deeds of a person, the sum of which make up his or her conduct. Act, by contrast, normally means something brought about rapidly or over a short period, especially in phrases with of (an act of God, an act of madness).

2. Both words have special meanings which are exclusive to each (an act of a play, an act in a variety show, military action, etc.), and in fixed expressions (to put on an act, caught in the act, to clean up one's act, to get one's act together, to take action, actions speak louder than words, where the action is, a piece of the action, etc.).

3. Action, in its modern use as a transitive verb meaning ‘to take action on (a decision or request, etc.)’ is best left to the evasive language of business managers

• (Dismissal will be actioned when the balance of probabilities suggests that an employee has committed a criminal act —Daily Telegraph, 1981).