act

AKT/ækt/

Pluralacts

Verbacts, acting, acted

23 meanings of act

Practice

1
nouncountable
Something a person does, including something they are in the middle of doing.
Helping the lost child was a kind act.
One careless act can start a forest fire.
Similardeed, action
Note
2
lawnouncountable
A law made by a parliament or congress, or a proposed law with that name.
Congress passed an act to protect the old forest.
The new act says every child must wear a seatbelt.
UsageLawmakers pass an act. In a name it has a capital: the Clean Air Act.
Similarlaw, statute
Note
3
verbintransitive
To do a certain job or serve a certain purpose, sometimes in place of someone else.
Her uncle will act as coach while Mr. Lee is away.
This old box can act as a table until the new one comes.
UsageUse act as: she will act as coach this week.
Similarserve, function
4
perform rolesverbintransitive
To play a part in a play, film or show.
She wants to act in the school play this year.
He acted in a TV commercial when he was a kid.
UsageYou act in a play or a film.
Similarperform, play
5
behaveverbintransitive
To behave in a certain way for a while.
Stop acting like a baby and tie your own shoes.
Please act politely while we're at the doctor's office.
UsageSay act like + a person or thing: stop acting like a baby.
Similarbehave
6
do somethingverbintransitive
To do something, especially to deal with a problem.
If you smell smoke, act fast and leave the building.
The mayor acted quickly when the storm hit.
UsageOften act fast or act now.
Similarmove
7
performernouncountable
A person or group who performs in a show, or the thing they perform.
The first act on stage was a singer with a guitar.
Our favorite act tonight was the team of dancers.
UsageOften the opening act: the first performer in a show.
Similarperformer
8
have an effectverbintransitive
To have an effect on something or someone.
The medicine acts fast to bring down a fever.
Lemon juice can act on the stain and lift it out.
UsageUse act on: the medicine acts on the pain.
Similarwork, operate
9
part of a playnouncountable
One of the main parts of a play, film or show.
Like a chapter in a book, but for a play or show.
The first act of the play ends with a big surprise.
We got snacks during the break between the two acts.
UsageSay the first act, the last act.
Note
10
pretendverbtransitive
To pretend to feel something or to be a certain way when you are not.
Act surprised when Grandma gives you the sweater she knitted.
He acted happy at the news, though it secretly upset him.
UsagePut a feeling word after it: act surprised.
Note

Less common meanings

11
pretensenouncountable
Behavior that is put on to make people believe something that is not true.
Like a mask that hides how someone really feels.
His tears were just an act to get out of trouble.
Her cheerful smile was just an act to hide how sad she felt.
UsageSay someone puts on an act when they pretend.
Similarpretense, front, show, sham, charade
Note
12
stage wellverbintransitive
To go well or badly when performed on stage, used about a play.
The script seemed dull on paper, but the play acted beautifully on opening night.
Some short comedies act better on stage than they read on the page.
UsageSay a play acts well when it works on stage.
Similarplay
Note
13
verbintransitive
To let advice, information, a belief, or a feeling lead you to do something.
You should act on the doctor's advice and rest for a week.
She acted on a strange feeling and called her sister.
UsageUse act on: act on the doctor's advice.
14
represent (law)verbintransitive
To do legal work for someone in a case or legal matter, as their lawyer.
Our lawyer agreed to act for us when we bought the house.
She acted for the family during the court case last year.
UsageA lawyer acts for a client.
Note
15
official recordnouncountable
An official paper that records something that was done or decided.
The notary kept the signed act in her files as proof of the sale.
The old acts of the town council show what it decided each year.
Similarrecord, document, instrument
16
decreeverbobsoleteScotlandtransitive
To make something into a law or an official order.
Note
17
motivateverbobsoletetransitive
To make someone or something move or do things.
Self-love, the spring of motion, acts the soul.
1733, [Alexander Pope], An Essay on Man.Here, acts means moves the soul to do things, makes it active.
Note
18
nounobsoleteuncountable
The state of really existing now, not just being possible.
The seeds of plants are not at first in act, but in possibility, what they afterward grow to be.
1594, Richard Hooker, Of the Lawes of Ecclesiastical PolitieHere, in act means really existing now, not just possible.
Note
19
verb
To do something that binds you, so you cannot take it back later.
20
noun
Something done one time and finished, not a job that goes on and on.
21
adverbslang
Short for actually: really or in fact, used in quick, casual texts and chats.
22
verb
In math, to move or change the pieces of another object by following set rules.
23
noun
A public test at some old English universities where a student defends an idea to earn a degree.

Practice

Can you tell the meanings of act apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.

Origin

It comes from Latin, from a word meaning "to do," and reached English through Old French.

Checked 31 Oct 2026 · 2 facts

Act derives ultimately from a Latin word meaning to do. en.wiktionary.org
Act reached English through Old French. en.wiktionary.org