ACTING

To do something.

Example: "If you don't act soon, you will be in trouble."

To do (something); to perform.

To perform a theatrical role.

Example: "I started acting at the age of eleven in my local theatre."

Of a play: to be acted out (well or badly).

To behave in a certain manner for an indefinite length of time.

Example: "A dog which acts aggressively is likely to bite."

To convey an appearance of being.

Example: "He acted unconcerned so the others wouldn't worry."

To do something that causes a change binding on the doer.

Example: "Act on behalf of john"

(construed with on or upon) to have an effect (on).

Example: "Gravitational force acts on heavy bodies."

To play (a role).

Example: "He's been acting shakespearean leads since he was twelve."

To feign.

Example: "He acted the angry parent, but was secretly amused."

(construed with on or upon, of a group) to map via a homomorphism to a group of automorphisms (of).

Example: "This group acts on the circle, so it can't be left-orderable!"

To move to action; to actuate; to animate.