(1):

(v. t.) To renounce upon oath; to forswear; to disavow; as, to abjure allegiance to a prince. To abjure the realm, is to swear to abandon it forever.

(2):

(v. t.) To renounce or reject with solemnity; to recant; to abandon forever; to reject; repudiate; as, to abjure errors.

(3):

(v. i.) To renounce on oath.