Sobriquet
SOBRIQUET, a nickname or a fancy name, usually a familiar name given by others as distinct from a " pseudonym " assumed as a disguise. Two early variants are found, sotbriquet and soubriquet; the latter form is still often used, though it is not the correct modern French spelling. The first form suggests a derivation from sot, foolish, and briquet, a French adaptation of Ital. brichetto, diminutive of bricco, ass, knave, possibly connected with briccom, rogue, which is supposed to be a derivative of Ger. brechen, to break; but Skeat considers this spelling to be due to popular etymology, and the real origin is to be sought in the form soubriquet. Littre gives an early 14th century soubsbriquet as meaning a " chuck under the chin," and this would be derived from soubs, mod. sous (Lat. sub), under, and briquet or bruchel, the brisket, or lower part of the throat.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)