UP IN ARMS

The phrase means to protest vigorously about something.

For example: The employees were up in arms over the management’s plan to discontinue five-day week policy.

The phrase started as a literal expression in the 16th century which became a more figurative idiomatic expression during the 17th century.

To be in arms or at arms was to be equipped with weapons and armour.

It most likely came from the definition of arms: weapons and ammunition, that a person is angry enough to have grabbed a weapon.

The first known use of the phrase in print is in Arthur Golding’s translation of Lyfe of Shatilion, 1576:

“The Protestantes that were up in armes in other places.”

It also appeared in Jonathan

Swifts first major work, A Tale of a Tub, published in 1704: “All the men of wit and politeness were immediately up in arms through indignation.”

It isn’t, however, clear why ‘arms’ was chosen as the name for weaponry. It may be as simple as a sword or club being seen as an extension of the arm.

‘Armour’ is just a form of defensive weaponry that a soldier was clad in. Like ‘vesture’, meaning ‘that which a person is dressed in’, that is, clothes, the ‘ure’ part may be translated as something like ‘collection of’.

The spelling would be more properly ‘armure’, which is how it was spelled in early texts; for example: Robert of Gloucester’s Metrical Chronicle, 1297:

He & hys armure...