"quick or rapid in action or motion, swift, lively," 1550s, as Scottish bruisk, which is of uncertain origin; perhaps an alteration of French brusque (see brusque). Related: Briskly; briskness.
1721 as a musical term, from Italian allegro "brisk, sprightly, cheerful," from Latin alacrem (nominative alacer) "lively, cheerful, brisk" (see alacrity). The same Latin word came into English 17c. as aleger "lively, brisk," from Old French alegre, from Latin alacris; and Milton used "L'Allegro" in its literal sense as a poem title (1632).
1834, "lively, nimble, active, brisk," American English, from northern British dialectal kipper "nimble, frisky," the origin of which is obscure.
1680s, from Italian vivace "brisk, lively," from Latin vivac-, stem of vivax "lively, vigorous; long-lived, enduring," from PIE root *gwei- "to live."
masc. proper name, also a surname (from early 13c.), also Galliard, from Old French Gaillart, from Proto-Germanic *Gailhard "lofty-hard;" or from Old French gaillard "lively, brisk, gay, high-spirited," from PIE root *gal- (3) "to be able, have power."
1740, in music, In music, indicating "quicker in time than andante, but not so quick as
allegro;" from Italian allegretto, diminutive of allegro (q.v.) "brisk, sprightly." Also as a noun, a musical movement in such time.