abjurer, abjuror 1. Someone who formally rejects or disavows a formerly held belief, usually under pressure. 2. Anyone who implies a firm and final rejecting or abandoning of a former belief or postion, often made under oath.adjurer, abjuror 1. Someone who charges, binds, or commands earnestly and solemnly, often under oath or the threat of a penalty. 2. To entreat or to request earnestly or solemnly.