‖n. [ F., without breeches. ] 1. 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. [ 1913 Webster ]

2. Hence, an extreme or radical republican; a violent revolutionist; a Jacobin. [ 1913 Webster ]

a. Pertaining to, or involving, sans-culottism; radical; revolutionary; Jacobinical. Carlyle. [ 1913 Webster ]

n. [ F. sans-culottisme. ] Extreme republican principles; the principles or practice of the sans-culottes. [ 1913 Webster ]