1. Someone who formally rejects or disavows a formerly held belief, usually under pressure: Joan became an abjurer when she was forced by a Medieval court of inquiry to give up her religious beliefs.
2. Anyone who implies a firm and final rejection or abandonment of a former belief or position, often made under oath: The two abjurers, Steven and Edward, met with the media to explain their joint decision to discontinue their previously held political commitments.