avow (v.)

c. 1300, "uphold, support, approve; stand by, back up (someone); declare openly, take sides openly, affirm;" mid-14c. "admit openly," from Anglo-French avouer, Old French avoer "acknowledge, accept, recognize," especially as a protector (12c., Modern French avouer), from Latin advocare "to call, summon, invite" (see advocate (n.)). A synonym of avouch (q.v.), which tends to contain the more technical, legal aspect of the word. Related: Avowed; avowing.