Act, v. i. 1. To exert power; to produce an effect; as, the stomach acts upon food.
2. To perform actions; to fulfill functions; to put forth energy; to move, as opposed to remaining at rest; to carry into effect a determination of the will.
He hangs between, in doubt to act or rest.
Pope.
3. To behave or conduct, as in morals, private duties, or public offices; to bear or deport one's self; as, we know not why he has acted so.
4. To perform on the stage; to represent a character.
To show the world how Garrick did not act.
Cowper.
To act asorfor, to do the work of; to serve as. — To act on, to regulate one's conduct according to. — To act up to, to equal in action; to fulfill in practice; as, he has acted up to his engagement or his advantages.