To renounce, deny, or disavow a profession, belief, or claim that one previously made.
From dis- (negation) + profess (from Latin profiteri, 'to declare publicly'). The prefix reverses the act of public declaration into a public disavowal.
Medieval monks used this term when they formally left their religious order—it's the opposite of taking vows, a kind of ceremonial un-professing that required witnesses and documentation.
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