Merriam-Webster Logo
SINCE 1828
Menu
×
1

act

noun \ ˈakt \
|Updated on: 12 Jun 2018

Definition of act

1 a : the doing of a thing : deed
  • an act of courage
b law : something done voluntarily
2 : the process of doing something : action
  • caught in the act
3 : the formal product of a legislative body : statute
  • an act of Congress
; also : a decision or determination of a sovereign, a legislative council, or a court of justice
4 : one of the principal divisions of a theatrical work (such as a play or opera)
  • a play in three acts
5 a : one of successive parts or performances (as in a variety show or circus)
  • a magic act
b : the performer or performers in such an act
  • a two-person comedy act
c : a performance or presentation identified with a particular individual or group
  • They took their act on the road.
d : the sum of a person's actions or effects that serve to create an impression or set an example
  • a hard act to follow
6 : a display of affected behavior : pretense
  • put on an act that deceived nobody
  • His friendly concern was just an act.
7 often capitalized : a formal record of something done or transacted
8 : a state of real existence rather than possibility
— into the act or in on the act
: into an undertaking or situation as an active participant
  • saw the success they were having and wanted to get in on the act

See act defined for English-language learners

See act defined for kids

Examples of act in a Sentence

  1. We were grateful for her many acts of kindness.

  2. the Civil Rights Act of 1964

  3. Please read act II, scene 1 of Shakespeare's Romeo and Juliet.

  4. In the first act, two characters are talking in a restaurant.

Recent Examples of act from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'act.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of act

Middle English acte, borrowed from Anglo-French & Latin; Anglo-French acte, act, borrowed partly from Latin āctus "driving of cattle, track for cattle, movement, activity, performance, part of a play" (action noun from agere "to drive (cattle), cause to move, do"), partly from Latin āctum (usually in plural) "thing done, public transaction, record," from neuter of āctus, past participle of agere — more at agent

act Synonyms

Synonyms

airs, charade, disguise, facade (also façade), front, guise, masquerade, playacting, pose, pretense (or pretence), put-on, semblance, show;

Near Antonyms

bluntness, candidness, candor, directness, forthrightness, frankness, openheartedness, outspokenness, plainspokenness, straightforwardness;

artlessness, genuineness, naïveté (also naivete);

Related Words

impersonation, performance, portrayal;

image, persona;

appearance, color, gloss;

camouflage, cloak;

affectation, deceit, deception, dissembling, dissimulation, double-dealing, duplicity, fakery, fraud, guile;

betrayal, double cross, faithlessness, falseness, falsity, infidelity, perfidy, treachery, treason, unfaithfulness;

excuse, pretext;

2

act

verb

Definition of act

acted; acting; acts
intransitive verb
1 : to take action : move
  • think before acting
  • acted favorably on the recommendation
2 : to conduct oneself : behave
  • act like a fool
3 a : to perform on the stage
  • began acting at the age of eight
b : to behave as if performing on the stage : pretend
  • seemed angry but was just acting
4 : to perform a specified function : serve
  • trees acting as a windbreak
5 : to produce an effect : work
  • wait for a medicine to act
6 : to give a decision or award
  • adjourned without acting on the bill
7 of a play : to be capable of being performed
  • a play that acts well
transitive verb
1 a : to represent or perform by action especially on the stage
  • will act the part of Romeo in tonight's play
b : feign, simulate
  • act indifference
c : impersonate
2 : to play the part of as if in a play
  • act the man of the world
3 : to behave in a manner suitable to
  • Act your age.
4 obsolete : actuate, animate
—

actability

play \ˌak-tə-ˈbi-lə-tē\ noun
—

actable

play \ˈak-tə-bəl\ adjective

See act defined for English-language learners

Examples of act in a Sentence

  1. He knew he had to act quickly.

  2. The government was slow to act.

  3. She acted on behalf of her father, who was not at the meeting.

  4. I believe that the killer acted alone.

  5. She had acted in self-defense when she killed her attacker.

  6. We were acting in the best interests of our children.

  7. We must act soon to end this crisis.

  8. She learned at an early age how to act properly in social situations.

  9. People are always telling me how I should act and what I should say.

  10. I noticed that the dog was acting funny this morning.

Recent Examples of act from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'act.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of act

Middle English acten "to act upon, adjudicate," in part derivative of act 1act, in part borrowed from Latin āctus, past participle of agere

act Synonyms

Synonyms

do, impersonate, interpret, perform, play, portray;

Related Words

depict, dramatize, render, represent;

act out, enact, pantomime, playact, role-play, take on;

overact, overplay, underplay;

ape, clown, ham, imitate, masquerade, mime, mimic, pose (as);

star (in);

coact, costar;

3

act

abbreviation

Definition of act

1 active
2 actor
3 actual

Other Performing Arts Terms

diva, dramaturgy, loge, prestidigitation, proscenium, supernumerary, zany

1

ACT

abbreviation

Definition of ACT

1 Action for Children's Television
2 Association of Classroom Teachers
3 Australian Capital Territory

See ACT defined for English-language learners

Other Education Terms

baccalaureate, colloquium, corequisite, dissertation, monograph, pedant, practicum, survey course, thesis

2

ACT

trademark \ ˌā-ˌsē-ˈtē \

Definition of ACT

—used for a standardized achievement test to evaluate suitability for college admission

Other Education Terms

baccalaureate, colloquium, corequisite, dissertation, monograph, pedant, practicum, survey course, thesis

ACT Defined for English Language Learners

act

noun

Definition of act for English Language Learners

  • : something that is done

  • : a law made by a group of legislators

  • : one of the main divisions of a play or opera

act

verb

Definition of act for English Language Learners

  • : to do something : to take action

  • : to behave in a particular way

  • : to behave in a way that is not sincere or honest

ACT Defined for Kids

1

act

noun \ ˈakt \

Definition of act for Students

1 : something that is done : deed
  • an act of bravery
2 : a law made by a governing body
3 : a main division of a play
4 : one of the performances in a show
  • a juggling act
5 : an insincere way of behaving
  • Her crying was just an act.
2

act

verb

Definition of act for Students

acted; acting
1 : to do something : move
  • It's important to act quickly in an emergency.
2 : to behave oneself in a certain way
  • He's been acting strangely.
3 : to perform as a character in a play
  • Both stars agreed to act in the movie.
4 : to perform a certain function
  • She'll act as our guide.
5 : to have a result : make something happen : work
  • The medicine acts on the heart.
— act up
: to behave badly

Medical Dictionary

1

act

noun \ ˈakt \

medical Definition of act

1 : a motor performance leading to a definite result
2 : a dealing with objects (as by moving, perceiving, or desiring them)
2

act

intransitive verb

medical Definition of act

1 : to perform an act : behave
2 : to produce an effect
  • wait for a medicine to act

act

abbreviation

medical Definition of act

active

Law Dictionary

1

act

noun

legal Definition of act

1 a : something done by a person in accordance with his or her free will
  • a tortious act
— see also actus reus
b : the failure to do something that one has a legal duty to do — called also negative act
2 a often capitalized : the formal product of a legislative body : the formally declared will of a legislature the final requirement of which is usually the signature of the proper executive officer : statute
  • an act of Congress
  • in furtherance of the purposes…of that act
  • —U.S. Code
b : a decision or determination of a sovereign, a legislative council, or a court of justice — compare bill 1
3 often capitalized : a formal record of something done or transacted
  • given as my free act and deed
2

act

intransitive verb

legal Definition of act

1 : to carry into effect a determination of the will : take action
2 : to discharge the duties of a specified office or post : perform a specified function —used with a prepositional phrase
  • declaring what officer shall then act as President
  • —U.S. Constitution art. II
3 : to give a decision or award (as by vote of a deliberative body or by judicial decree) —often used with on
  • adjourned with several important matters still not acted on
—

actor

play \ˈak-tər\ noun

Learn More about act

  1. See words that rhyme with act Thesaurus: All synonyms and antonyms for act Spanish Central: Translation of act Nglish: Translation of act for Spanish speakers Britannica English: Translation of act for Arabic speakers

Seen and Heard

What made you want to look up act? Please tell us where you read or heard it (including the quote, if possible).

show hide

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

skirl

play

to emit the high shrill tone of bagpipes

Get Word of the Day daily email!

TRENDING NOW

  1. asylum 'protection from arrest and extradition given especially to political refugees'

  2. insubordinate 'disobedient to authority'

  3. promulgate 'to make known by open declaration'

  4. epochal 'momentous or unparalleled'

  5. clemency 'merciful treatment of someone who could be given harsh punishment'

SEE ALL

BROWSE DICTIONARY

ACS
ACT
act

Test Your Vocabulary

Words for Summer: A Quiz

  • a-closeup-of-a-sunflower
  • Which of the following words means “of or relating to summer”?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

Ask the Editors

Word Games