When you avouch, you assert that something is true. An accused man might be acquitted if several eyewitnesses avouch that he was nowhere near the scene of the crime.

Avouch is an extremely old-fashioned way to say another (only slightly old-fashioned) word, avow. Use either word to mean "assert" or "declare." While it's unusual to hear people use avouch, it's common to say something like, "I'll vouch for my friend," meaning you'll give evidence or make a guarantee on your friend's behalf. The root of avouch is the Latin advocare, "call to as a witness."

Definitions of avouch
  1. verb
    admit openly and bluntly; make no bones about
    synonyms: avow
    see moresee less
    refuse to acknowledge; disclaim knowledge of; responsibility for, or association with
    type of:
    acknowledge, admit
    declare to be true or admit the existence or reality or truth of
Word Family