up in arms

Meanings

adjectiveup in arms (not comparable)

figurativelynot comparableAngry; incensed; preparing for a fight.
Near-synonym: in the streets
3 more examples
The union members are up in arms over threats of pay cuts.
Lan[caster]. My lord, will you take armes against the king? Bish[op]. What neede I, God himselfe is vp in armes, When violence is offered to the church.
1594, Christopher Marlow[e], The Troublesome Raigne and Lamentable Death of Edward the Second, King of England: […], London: […] [Eliot’s Court Press] for Henry Bell, […], published 1622, →OCLC, [Act I]
Allworthy was of a cooler Disposition than the good Woman, whose Spirits were all up in Arms in the Cause of her Friend.
1749, Henry Fielding, chapter 5, in The History of Tom Jones, a Foundling, volume III, London: A[ndrew] Millar, […], →OCLC, book XVIII, page 301
Synonyms: in the streets
figurativelynot comparableVigourously protesting against something.
Is file-sharing, which has the recording industry so up in arms, the “dark side” of open-source attitudes?
2003 September 28, David Diamond, “The Way We Live Now: 9-28-03: Questions for Linus Torvalds; The Sharer”, in The New York Times Magazine
2 more examples
Many artists are up in arms about the new AI programs — and with good reason. Some are furious that their works have been used as training data without their permission.
2023 March 24, Nathan J. Robinson, “The Problem With AI Is the Problem With Capitalism”, in Jacobin
Europe has not, over the course of more than two years of Israel’s ongoing genocide in the Gaza Strip, managed to be sufficiently up in arms over the mass slaughter, preferring to go the route of superficial criticism and de facto complicity.
2026 January 22, Belén Fernández, “Europe cannot condemn colonialism à la carte”, in Al Jazeera English
not comparableuncommonliteralArmed for battle; prepared for or engaged in warfare.
Near-synonym: at arms (sometimes synonymous)
2 more examples
March on, march on, ſince we are vp in Armes, If not to fight with forraine Enemies, Yet to beat downe theſe Rebels here at home.
c. 1593 (date written), William Shakespeare, “The Tragedy of Richard the Third: […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act IV, scene iv], page 199, column 2
News was brought him, that the Scythians, and barbarous nations of the North, were again up in arms, and invading the empire with furious impetuosity.
1769, [Oliver] Goldsmith, chapter 18, in The Roman History, from the Foundation of the City of Rome, to the Destruction of the Western Empire. […], volume II, London: […] S. Baker and G. Leigh, […]; T[homas] Davies, […]; and L. Davis, […], →OCLC, page 372
Synonyms: at arms