Chip on your shoulder
A perceived grievance or sense of inferiority.
The word chip has several meanings; the one that we are concerned with here is the earliest known of these, namely 'a small piece of wood, as might be chopped, or chipped, from a larger block'. The phrase 'a chip on one's shoulder' is reported as originating with the nineteenth century U.S. practice of spoiling for a fight by carrying a chip of wood on one's shoulder, daring others to knock it off. This suggested derivation has more than the whiff of folk-etymology about it. Anyone who might be inclined to doubt that origin can take heart from an alternative theory. This relates to working practices in the British Royal Dockyards in the 18th century. In Day and Lunn's The History of Work and Labour Relations in the Royal Dockyards, 1999, the authors report that the standing orders of the [Royal] Navy Board for August 1739 included this ruling:
"Shipwrights to be allowed to bring [chips] on their shoulders near to the dock gates, there to be inspected by officers".
The permission to remove surplus timber for firewood or building material was a substantial perk of the job for the dock workers. A subsequent standing order, in May 1753, ruled that only chips that could be carried under one arm were allowed to be removed. This limited the amount of timber that could be taken and the shipwrights were not best pleased about the revoking of their previous benefit. Three years later, for this and other reasons, they went on strike.
Hattendorf, Knight et al., in British Naval Documents, 1204 - 1960, record a letter which was sent by Chatham Dockyard officers to the Navy Board, relating to the 1756 dockyard workers' strike at Chatham. The letter records a comment made by a shipwright who was stopped at the yard's gates:
"Are not the chips mine? I will not lower them."
It goes on to report that "Immediately the main body pushed on with their chips on their shoulders."
That's a nice story and does connect an incident concerning chips and shoulders with a belligerent attitude. We need to be a little wary of swallowing that derivation whole however. The problem with it is that the phrase isn't known to be recorded in print in England with its figurative meaning anywhere near the 18th century. The first such record by an English author doesn't seem to be until the 1930s in fact, in Somerset Maugham's Gentleman in the Parlour:
"He was a man with a chip on his shoulder. Everyone seemed in a conspiracy to slight or injure him."
A gap of nearly 200 years between the use of a phrase and the incident that supposedly spawned it in the same country is hard to explain. In my humble opinion, the 'chips on shoulders' report dating from 1756 refer literally to just that, chips carried on shoulders. There's no evidence at all to suggest 'a chip on one's shoulder' existed as a figurative phrase until the 19th century.
The confrontational challenge to knock a chip of wood off someone's shoulder does after all appear to be the correct derivation. Circumstantial evidence is all we have to go on here, but that clearly points to a 19th century US coinage. The earliest printed citations that I can find that refer to chips on shoulders are all from America, which the OED states quite firmly to be the source of the phrase; for example:
The American writer and historian James Kirke Paulding's Letters from the South, 1817:
"A man rode furiously by on horseback, and swore he'd be d----d if he could not lick any man who dared to crook his elbow at him. This, it seems, is equivalent to throwing the glove in days of yore, or to the boyish custom of knocking a chip off the shoulder."
In 1830 the New York newspaper The Long Island Telegraph printed this:
"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 actual phrase 'chip on his shoulder' appears a little later, in the Weekly Oregonian 1855:
"Leland, in his last issue, struts out with a chip on his shoulder, and dares Bush to knock it off."