The Collaborative International Dictionary
Sans-culotte \Sans`-cu`lotte"\ (F. ?; E. ?), n. [F., without breeches.]
A fellow without breeches; a ragged fellow; -- a name of reproach given in the first French revolution to the extreme republican party, who rejected breeches as an emblem peculiar to the upper classes or aristocracy, and adopted pantaloons.
Hence, an extreme or radical republican; a violent revolutionist; a Jacobin.
Douglas Harper's Etymology Dictionary
also sansculotte, "lower-class republican of the French Revolution," 1790, from French, literally "without breeches;" see sans + culottes. Usually explained as referring to the class whose distinctive costume was pantalons (long trousers) as opposed to the upper classes, which wore culottes (knee-breeches), but this is not certain. Related: Sans-culottes; sans-culotterie.
Wiktionary
n. A plebian Parisian, especially a lower-class republican during the French Revolution. (from 18th c.)
Usage examples of "sans-culotte".
Here was one man not trying to emulate the Revolutionary prototype of the sans-culotte —no red cap or huge mustache or workman's carmagnole jacket for him.
The sans-culotte journalists of England, the agents and spies of the Revolutionary Government, had taken their revenge of the frequent snubs inflicted upon them by the young actress, and in those days the fact of being unwelcome in France was apt to have a more lurid and more dangerous significant.