Webster's Revised Unabridged Dictionary · 1913

Avouch

Avouch ({not transcribed}) , transitive verb

[Old French avochier, Late Latin advocare to recognize the existence of a thing, to advocate, from Latin advocare to call to; ad + vocare to call. Compare Avow to declare, Advocate, and see Vouch, transitive verb]

1.
To appeal to; to cite or claim as authority. [Obsolete]
They avouch many successions of authorities. — Coke
2.
To maintain a just or true; to vouch for.
We might be disposed to question its authenticity, it if were not avouched by the full evidence. — Milman
3.
To declare or assert positively and as matter of fact; to affirm openly.
If this which he avouches does appear. — Shakespeare
Such antiquities could have been avouched for the Irish. — Spenser
4.
To acknowledge deliberately; to admit; to confess; to sanction.
Thou hast avouched the Lord this day to be thy God. — Deut. xxvi. 17

Avouch ({not transcribed}) , noun

Evidence; declaration. [Obsolete]
The sensible and true avouch Of mine own eyes. — Shakespeare