Warrant
Middle English (in the senses ‘protector’ and ‘safeguard’, also, as a verb, ‘keep safe from danger’): from variants of Old French guarant (noun), guarantir (verb), of Germanic origin; compare with guarantee.
wiktionary
The noun is derived from Middle English warant(“protector; guard, shield, protection”), from Anglo-Norman warrant, Old Northern French warant, warand, a variant of Old French guarant, garant, garand(“assurance, guarantee; authorization, permission; protector; protection, safety”) (modern French garant), [1] from Frankish *warand, present participle of *warjan(“to fend off; to stop, thwart”). The word is cognate with Old High German werento(“guarantor”).
The verb is derived from Middle English warrant, waranten(“to give protection; to protect, shield; to assure, pledge, promise; to guarantee”), from Anglo-Norman warantir, warandir, warentir, and Old Northern French warandir, warantir, variant forms of Old French guarantir(“to protect”) (modern French garantir), [2] a Romance formation from the noun guarant: see above.
etymonline
warrant (n.)
c. 1200, "protector, defender," from Old North French warant "defender; surety, pledge; justifying evidence" (Old French garant), from Frankish *warand, from Proto-Germanic *war- "to warn, guard, protect" (source also of Old High German werento "guarantor," noun use of present participle of weren "to authorize, warrant;" German gewähren "to grant"), from PIE root *wer- (4) "to cover."
Sense evolved via notion of "permission from a superior which protects one from blame or responsibility" (early 14c.) to "document conveying authority" (1510s). A warrant officer in the military is one who holds office by warrant (as from a government department), rather than by commission (from a head of state).
warrant (v.)
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.
