verb

• (transitive)
  "Nor need I ſpeak my Deeds, for thoſe you ſee, The Sun and Day are Witneſſes for me. Let him who fights unſeen, relate his own, And vouch the ſilent Stars, and conſcious Moon."
• (transitive)
  "But the most catholike and renoumed doctours of Christes religion in the corroboration of their argumentes and sentences, do alledge the same histories and vouche (as I mought say) to their ayde the autoritie of the writars."
• (transitive)
  "Nay tis moſt credible, we heere receiue it, A certaintie vouch'd from our Coſin Auſtria, […]"
• (transitive)
  "If a Man ſucceeds in any Attempt, though undertook with never ſo much Folly and Raſhneſs, his Succeſs ſhall vouch him a Politician; and good Luck ſhall paſs for deep Contrivance: […]"

noun

• (archaic or obsolete) An assertion, a declaration; also, a formal attestation or warrant of the correctness or truth of something.
  "VVho will beleeue thee Iſabell? My vnſoild name, th' auſteereneſſe of my life, My vouch againſt you, and my place i'th State, VVill ſo your accuſation ouer-vveigh, That you ſhall ſtifle in your ovvne report, And ſmell of calumnie."