act

verb

1》 take action; do something.

    ↘(act up) informal behave badly.

2》 (act for/on behalf of) represent on a contractual or legal basis.

    ↘[as adjective acting] temporarily doing the duties of another.

3》 take effect or have a particular effect.

4》 perform a fictional role in a play or film.

    ↘behave so as to appear to be: I acted dumb.

    ↘(act something out) perform a narrative as if it were a play.

noun

1》 a thing done.

2》 a simulation or pretence.

    ↘a particular type of behaviour or routine: he did his Sir Galahad act.

3》 Law a written ordinance of Parliament, Congress, etc.

4》 dated a record of the decisions or proceedings of a committee or an academic body.

5》 a main division of a play, ballet, or opera.

6》 a set performance: her one-woman poetry act.

Phrases

act of God an instance of uncontrollable natural forces in operation.

act of grace a privilege or concession that cannot be claimed as a right.

get (or be) in on the act informal become (or be) involved in a particular activity, in order to gain an advantage.

Derivatives

actability noun

actable adjective

acting noun

Origin

ME: from L. actus 'event, thing done', from act-, agere 'do, act', reinforced by Fr. acte.