/ ækt; NAmE / noun , verb
■ noun
STH THAT SB DOES
1.
[ C ] a particular thing that sb does :
an act of kindness
acts of terrorism
The murder was the act of a psychopath.
a criminal act
➡ note at action
LAW
2.
[ C ] a law that has been passed by a parliament :
an Act of Congress
the Higher Education Act 2002
PRETENDING
3.
[ sing. ] a way of behaving that is not sincere but is intended to have a particular effect on others :
Don't take her seriously—it's all an act.
You could tell she was just putting on an act .
IN PLAY / ENTERTAINMENT
4.
[ C ] one of the main divisions of a play, an opera , etc. :
a play in five acts
The hero dies in Act 5, Scene 3.
5.
[ C ] one of several short pieces of entertainment in a show :
a circus / comedy / magic act
6.
[ C ] a performer or group of musicians :
They were one of rock's most impressive live acts.
•
IDIOMS
- act of God
- be / get in on the act
- do, perform, stage a disappearing / vanishing act
- get your act together
- a hard / tough act to follow
- in the act (of doing sth)
—more at clean verb , read verb
■ verb
DO STH
1.
[ v ] to do sth for a particular purpose or in order to deal with a situation :
It is vital that we act to stop the destruction of the rainforests.
The girl's life was saved because the doctors acted so promptly.
He claims he acted in self-defence.
BEHAVE
2.
[ v ] to behave in a particular way :
John's been acting very strangely lately.
Stop acting like spoilt children!
HELP NOTE : In spoken English people often use like instead of as if or as though in this meaning, especially in NAmE :
She was acting like she'd seen a ghost.
This is not considered correct in written BrE .
PRETEND
3.
to pretend by your behaviour to be a particular type of person :
[ v - n ]
He's been acting the devoted husband all day.
[ v - adj ]
I decided to act dumb.
PERFORM IN PLAY / MOVIE
4.
to perform a part in a play or film / movie :
[ v ]
Have you ever acted?
Most of the cast act well.
[ vn ]
Who's acting (= taking the part of) Hamlet?
The play was well acted.
PERFORM FUNCTION
5.
[ v ] act as / like sth to perform a particular role or function :
Can you act as interpreter?
hormones in the brain that act like natural painkillers
HAVE EFFECT
6.
[ v ] act (on sth) to have an effect on sth :
Alcohol acts quickly on the brain.
•
IDIOMS
see age noun , fool noun , own verb
•
PHRASAL VERBS
- act for / on behalf of sb
- act on / upon sth
- act sth out
- act up
••
WORD ORIGIN
late Middle English : from Latin actus event, thing done, act- done, from the verb agere , reinforced by the French noun acte .