early 14c. (late 12c. in surnames), "brave, courageous, intrepid in danger," from Anglo-French vaylant, and Old French vaillant "stalwart, brave," present participle adjective from valoir "be worthy," originally "be strong," from Latin valere "be strong, be well, be worth, have power, be able, be in health," from PIE root *wal- "be strong" (cognates: Old English wealdan "to rule," Old High German -walt, -wald "power" (in personal names), Old Norse valdr "ruler," Old Church Slavonic vlasti "to rule over," Lithuanian valdyti "to have power," Celtic *walos- "ruler," Old Irish flaith "dominion," Welsh gallu "to be able"). As a noun, "valiant person," from c.1600. Related: Valiantly.