late 13c., "to keep safe from danger," from Old North French warantir "safeguard, protect; guarantee, pledge" (Old French garantir), from warant (see warrant (n.)). Meaning "to guarantee to be of quality" is attested from late 14c.; sense of "to guarantee as true" is recorded from c. 1300. Related: Warranted; warranting; warrantable.[warrant etymology, warrant origin, 英语词源]