noun

1. a thing done; deed
2. an action; doing caught in the act of stealing
3. a decision (of a court, legislature, etc.); law; decree
4. a document formally stating what has been done, made into law, etc.
5. one of the main divisions of a drama or opera
6. any of the separate performances on a variety program
7. a show of feeling or behavior that is not sincere and is put on just for effect

Etymology: ME < OFr acte < L actus, a doing or moving, actum, thing done, pp. of agere, to do < IE base *a-, to drive, do > Gr agein, to lead

transitive verb

1. to play the part of
2. to perform in (a play)
3. to behave in a way suitable for don't act the child

Etymology: ME acten < L actus: see actthe

intransitive verb

1. to perform in a play, film, etc.; play a role
2. to behave as though playing a role
3. to be suited to performance: said of a play or a role
4. to behave; comport oneself act like a lady
5. to do something we must act now to forestall disaster
6. to serve or function the fence acts as a barrier
7. to serve as spokesman or substitute (for) he's acting for the committee
8. to have an effect acids act on metal
9. to appear to be he acted very angry