Q From Jessica Ronaldson in the USA: I was wondering what the origin of the phrase chip on the shoulder was?
A Very occasionally, someone asks about a phrase for which a good explanation exists. This is one of those rare cases. Let us pause a moment to celebrate.
It is American, first recorded in the Long Island Telegraph for 20 May 1830: “When two churlish boys were determined to fight, a chip would be placed on the shoulder of one, and the other demanded to knock it off at his peril”. The same idea is mentioned in the issue of The Onondaga Standard of Syracuse, New York, for 8 December the same year: “‘He waylay me,’ said I, ‘the mean sneaking fellow — I am only afraid that he will sue me for damages. Oh! if I only could get him to knock a chip off my shoulder, and so get round the law, I would give him one of the soundest thrashings he ever had.’”
It seems to have been a challenge in the same spirit as a medieval knight throwing down his gauntlet. If your opponent picked up the glove, or knocked the chip of wood off your shoulder, the challenge was accepted and the fight was on. Later it came to suggest somebody who shows a belligerent attitude, acting as though he were spoiling for a fight; the chip was figurative, but the idea was the same.