Early 18th century (in an earlier sense). From French mousquetaire footsoldier armed with a musket, cavalry soldier belonging to one of the two companies of the king's household from mousquet + -aire. With use as adjective compare French mousquetaire designating items of fashionable costume. The Mousquetaires (disbanded in 1775 and again, after a brief revival, in 1815), were popularized in fiction in the mid 19th cent. by Alexandre Dumas père's series of novels.