vouch
v.to say that you believe someone is honest or that something is true because you have personal experience with them. You use this when you want to support someone's reputation.
v.to assert or confirm as a result of one's own experience that something is true or that someone is of good character. Typically used in professional or social contexts to provide a personal guarantee.
“I can vouch for his honesty.”
“Since I have worked with her for five years, I can vouch for her ability to handle complex projects under pressure.”
“While the candidate's resume was impressive, the committee waited for a former colleague to vouch for his interpersonal skills before making a final offer.”
Intransitive; almost always followed by the preposition 'for' and a noun phrase object.
The verb is intransitive and requires the preposition 'for' before the object.
“In them, Oz vouched for the quality of Raoult’s research.”
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 8.1 (“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 from Anglo-Norman and Old French voucher a garant. The noun is derived from the verb.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.