vouch
(vaʊtʃ) verb 1 (intransitive; usually foll by for) to give personal assurance; guarantee ■ I'll vouch for his safety
2 (when tr, usually takes a clause as object; when intr, usually foll by for) to furnish supporting evidence (for) or function as proof (of)
3 (transitive) English legal history to summon (a person who had warranted title to land) to defend that title or give up land of equal value
4 (transitive) archaic to cite (authors, principles, etc) in support of something
5 (transitive) obsolete to assert
▷ noun 6 obsolete the act of vouching; assertion or allegation
[C14: from Old French vocher to summon, ultimately from Latin vocāre to call]