vouch

Etymology

The verb is derived from Middle English vouchen (“to call, summon; to provide; to make available, proffer; to affirm, declare formally”) [and other forms], from Anglo-Norman vocher, voucher, woucher, and Old French vocher, voucher, vochier (“to call, summon; to claim; to call upon, invoke; to denounce”) [and other forms], from Vulgar Latin *vocicāre, derived from Latin vocāre (“to call, summon; to call upon, invoke; to designate, name; to bring or put (into a condition or state”), ultimately from Proto-Indo-European *wekʷ- (“to sound out; to speak”). Verb sense 6.1 (“to summon (someone) into court to establish a warranty of title to land”) in the form vouch to warrant or vouch to warranty is a calque of Anglo-Norman and Old French voucher a garant. The noun is derived from the verb.

verb

1. (transitive)
   1. To call on (someone) to be a witness to something.
   2. To cite or rely on (an authority, a written work, etc.) in support of one's actions or opinions.
   3. To affirm or warrant the correctness or truth of (something); also, to affirm or warrant (the truth of an assertion or statement).
   4. To bear witness or testify to the nature or qualities (of someone or something).
   5. To back, confirm, or support (someone or something) with credible evidence or proof.
   6. (archaic) Synonym of vouchsafe (“to condescendingly or graciously give or grant (something)”)
   7. (archaic or obsolete) To assert, aver, or declare (something).
   8. (law)
      1. In full vouch to warrant or vouch to warranty: to summon (someone) into court to establish a warranty of title to land.
      2. Followed by over: of a vouchee (a person summoned to court to establish a warranty of title): to summon (someone) to court in their place.
      3. (obsolete) To guarantee legal title (to something).
2. (intransitive) Often followed by for.
   1. To bear witness or testify; to guarantee or sponsor.
      I can vouch that he wasn’t at the scene of the crime.
   2. To provide evidence or proof.
   3. To express confidence in or take responsibility for (the correctness or truth of) something.

noun

1. (archaic or obsolete) An assertion, a declaration; also, a formal attestation or warrant of the correctness or truth of something.