If some individual should adopt an undue familiarity and derisively chuck you under the chin, you might think of several unkind words for the action and your assailant. Sobriquet would not be among them, though a direct connection exists.
It’s a mildly weird word in form and spelling as well as sense. In the 400 years it has been in British English it has never quite lost its French pronunciation, perhaps because it undoubtedly looks French. In other English-speaking countries, a spelling pronunciation that sounds the t is now also heard. It has never quite settled on a single spelling either, the soubriquet version that reflects an older French form still being fairly common.
It means a nickname.
A 90-minute drive away is the beautiful Spanish cathedral city of Salamanca, the warm glow of its sandstone buildings giving rise to the sobriquet the Golden City.
The Times, 13 Oct. 2012.
Nicknames can be familiar in a good sense — to have one bestowed can be a mark of acceptance. But they may instead be derisive (and divisive), picking on a negative characteristic of a person to push him or her away from membership of a group. The former British prime minister Margaret Thatcher may have been given the sobriquet of the Iron Lady in admiration of her steadfastness, but it wasn’t always meant as a compliment.
We can’t be sure of the origin of the term. In French, it grew out of the fifteenth-century soubricquet for a pat or tap under the chin. But there’s doubt about the second part of the word: it has been suggested that it might be from Old French bequet, the nose, or from brechet, the breast or chest, the Old French equivalent of English brisket.
Today, French lexicographers broadly agree with Pierre Guiraud’s suggestion in his Dictionnaire des étymologies obscures. He feels it’s actually from briquet, in modern French a cigarette lighter but which was anciently the metal part of a flint and steel, used to strike sparks to start a fire. The movements involved, called battre le briquet, to strike a light, were thought to resemble the insulting gesture of repeatedly rubbing one’s index finger beneath a person’s chin. So it came to mean a derisive nickname, the sense it still has in modern French.
In English, it has always meant either sort of nickname, whether derogatory or of affection and friendship.