"decisive," mid-15c., legal term, from Anglo-French peremptorie, from Middle French peremtoire, from Latin peremptorius "destructive, decisive, final," from peremptor "destroyer," from perimpere "destroy, cut off," from per- "away entirely, to destruction" (see per) + emere "to take" (see exempt, adj.). Of persons or their words, "certain, assured, brooking no debate," 1580s. Related: Peremptorily.