act
Pluralacts
Pluralacts
- 1Something a person does; a single deed or action, including one seen while it is happening.
Returning the wallet was an act of honesty.
Historians still debate whether the bombing was an act of war or an act of desperation.
Note
Its favorite frame is act of followed by a quality: an act of goodwill, or Wordsworth's "little, nameless, unremembered acts / Of kindness and of love." The frame presents one deed as a sample of a virtue.
Checked 1 Nov 2026 · 1 fact
- Wordsworth wrote the quoted lines. gutenberg.org
- 2A law passed by a legislature; in the US also a bill proposed under that name.
The act established a national park along the river.
Lawmakers amended the act twice before it finally took effect.
UsageA law's name takes a capital: the Clean Air Act. Lawmakers pass, amend or repeal an act.
Note
American usage also stretches the word to a bill not yet passed, so context tells you whether the measure has actually passed.
- 3Followed by as: to serve in a particular role, post, or function, sometimes taking the place of someone else.
The deputy mayor will act as mayor until the special election.
The sofa in the den acts as a spare bed when guests stay over.
UsageFor a temporary post, the adjective acting goes before the title: acting director, acting president.
- 4To perform a role in a play, film or other show, or to play a particular character.
After college she moved to New York to act on stage.
He has acted professionally since he was eleven.
UsageYou act in a play or film, or act on stage. To name the role, play is usual: she plays Juliet.
- 5To behave in a particular manner, especially over a period of time.
He's been acting strangely ever since the accident.
New employees often act cautiously until they learn the office culture.
UsageFollowed by an adverb or like: acting strangely, act like a baby.
Similarbehave
- 6To do something; to take action, or carry something out.
Regulators must act before the practice spreads further.
The school board acted within a week of receiving the complaint.
UsageOften used with words of speed or urgency: act fast, act quickly, act now.
Similarmove
- 7A performer or group appearing in a show, or the routine they perform.
The opening act warmed up the crowd for nearly an hour.
By the late nineties, the band had become the biggest touring act in the country.
UsageCommon phrases: the opening act, the headline act, a touring act.
Similarperformer
- 8
- 9A major division of a play, opera, film or other dramatic work.
The villain isn't revealed until the final act.
Shakespeare's plays are traditionally divided into five acts.
UsageCommon patterns: the second act, the final act, a play in three acts.
Note
Drama's largest unit, counted the way playbills count it. Orczy's man in the corner likens a case to "a tragedy in a prologue and three acts." Scenes sit inside acts, so "the first scene of the second act" is a precise address within a play.
Checked 1 Nov 2026 · 2 facts
- Acts are major dramatic divisions and can contain scenes. en.wikipedia.org
- Scenes are subdivisions within acts. en.wikipedia.org
- 10To pretend to be or feel something; to put on an appearance of a quality, as in act surprised.
She acted indifferent, though the criticism stung.
Diplomats sometimes act enthusiastic about proposals they intend to bury.
UsageFollowed by an adjective for the feeling or stance: act surprised, act indifferent.
Note
The past participle works as an adjective meaning "pretended," as in Dryden's Virgil of 1697: "With acted fear the villain thus pursued." Acted fear marks an emotion as staged, a compact and slightly literary alternative to feigned.
Checked 1 Nov 2026 · 3 facts
- John Dryden translated the work containing the quotation. gutenberg.org
- Dryden's translation of Virgil was first published in 1697. openbook.lib.utah.edu
- The quoted words occur in Dryden's translation. gutenberg.org
Less common meanings
- 11A way of behaving put on for show, often to deceive, as in it's all an act.
Her enthusiasm for the merger was an act; she'd already accepted a job elsewhere.
The limp turned out to be an act designed to win the jury's sympathy.
UsageSet phrases: put on an act, it's all an act, just an act.
Similarpretense, front, show, sham, charade
Note
Here a display of behavior is a cover for what someone really feels. Its natural question sets it against sincerity, as in Tate McRae's "Greedy" (2023), which asks whether a show of feeling is genuine or only a performance. Just an act is the usual way to dismiss a show as false.
- 12Of a play: to come across well or badly in performance.
Critics agreed the comedy acted far better than its thin plot suggested.
Plays heavy with monologue rarely act well before a restless audience.
UsageUsually with an adverb, the way a book reads well: the play acts well, acts badly.
Similarplay
Note
Here the play itself is the subject, the way a book reads well. Effiong Johnson's Play Production Processes speaks of a play that "acts delightfully well before the audience," and adds that "if the play acts well, the director gets the credits."
Checked 1 Nov 2026 · 3 facts
- Effiong Johnson wrote Play Production Processes. xlibris.com
- Johnson's book contains the phrase about a play acting delightfully well before the audience. en.wiktionary.org
- Johnson's book says that the director receives the credits if the play acts well. en.wiktionary.org
- 13To do something in response to, or in line with, a piece of advice or information, a belief, or a feeling; used with on or upon.
Investors who act on rumors tend to lose money.
Police acted upon an anonymous tip and searched the warehouse.
UsageFollowed by on or upon and the reason: act on a tip, act on her advice.
- 14To carry out work as someone's legal representative in a particular legal matter.
The firm declined to act in the merger because of a conflict of interest.
He has acted for the publisher in every libel dispute since 2010.
UsagePatterns: act for a client, act in a matter. Alone, act assumes the matter is already known.
Note
A lawyer's word for taking on a matter. The usual patterns are act for a client and act in a matter, and a lawyer normally needs the client's instructions before taking any step.
Checked 3 Nov 2026 · 1 fact
- A lawyer normally needs the client's instructions before acting on the client's behalf. sra.org.uk
- 15A formal or official record of a thing done or decided, drawn up and kept as evidence.
The notary prepared an act certifying the transfer of the property.
Historians consulted the acts of the council to establish what had been decided.
Similarrecord, document, instrument
- 16To enact or decree (a law, order, or measure).
Note
A Scottish use, now obsolete, built on the same idea as the statute noun. Where a governing body today enacts or decrees a measure, in Scotland it could once simply act it.
Checked 1 Nov 2026 · 3 facts
- The sense is Scottish and obsolete. en.wiktionary.org
- This sense has the same legislative idea as the noun meaning a statute. en.wiktionary.org
- In historical Scottish usage, act could transitively mean enact or decree. en.wiktionary.org
- 17To move a person or thing to action; to actuate or animate.
Self-love, the spring of motion, acts the soul.
1733, [Alexander Pope], An Essay on Man.Note
An obsolete causative use: the subject is a motive or principle, and the object is what it sets moving. Pope's An Essay on Man (1733) has "Self-love, the spring of motion, acts the soul." When you meet it in older writing, read it as drives or animates.
Checked 1 Nov 2026 · 6 facts
- Act had an obsolete transitive causative sense meaning actuate or animate. en.wiktionary.org
- The described construction has a motivating principle acting upon what it animates, as in Pope's example. en.wikisource.org
- Alexander Pope wrote An Essay on Man. en.wikipedia.org
- 1733 is the first-publication year relevant to the quotation, which occurs in Epistle II; the final epistle followed in 1734. gutenberg.org
- The quoted words occur in Pope's An Essay on Man. en.wikisource.org
- Drives or animates accurately paraphrases this historical sense. en.wiktionary.org
- 18Actuality; the state of being real and realized, as opposed to merely potential.
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 PolitieNote
A learned sense, now obsolete, that lives on in an old contrast between being in act and being in possibility. Richard Hooker, writing in the 1590s, says the seeds of herbs and plants "at the first are not in act but in possibility that which they afterwards grow to be." Recognize it when reading older prose.
Checked 1 Nov 2026 · 2 facts
- Older prose contrasts being actual with being possible using 'in act' and 'in possibility'. merecatholicity.com
- Hooker's passage dates from the 1590s. oll-resources.s3.us-east-2.amazonaws.com
- 19To do something that brings about a change that is binding on the person who does it.
- 20Something done once and for all, as distinct from a work, which is ongoing.
- 21Short for actually: in fact or really, used in casual texting and online writing for emphasis or surprise.
- 22To possess an action on another structure, as a group does on a set or a ring does on a module by scalar multiplication.
- 23A thesis publicly maintained at certain English universities by a candidate for a degree, or to demonstrate a student's proficiency.
Showing meanings only.
Practice
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Origin
Latin agere ("to do, to act"), which goes back to Proto-Indo-European *h₂éǵeti, gave āctum ("decree, law"), whose plural ācta meant "register of events." This passed through Old French acte into Middle English acte. The word partly replaced the older deed, from Old English dǣd.
Checked 1 Nov 2026 · 7 facts
- Latin agere means “to do, to act.” en.wiktionary.org
- Latin agere ultimately derives from Proto-Indo-European *h₂éǵeti. en.wiktionary.org
- Latin agere gave āctum, meaning “decree, law.” en.wiktionary.org
- Ācta is the plural of āctum and meant “register of events.” en.wiktionary.org
- The word passed through Old French acte into Middle English acte. en.wiktionary.org
- Act partly replaced the older word deed. en.wiktionary.org
- Deed derives from Old English dǣd. en.wiktionary.org