The Collaborative International Dictionary of English v.0.48:

Abjure \Ab*jure"\, v. i.
   To renounce on oath. --Bp. Burnet.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Abjure \Ab*jure"\, v. t. [imp. & p. p. Abjured; p. pr. & vb.
   n. Abjuring.] [L. abjurare to deny upon oath; ab + jurare
   to swear, fr. jus, juris, right, law; cf. F. abjurer. See
   Jury.]
   1. 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.
      [1913 Webster]

   2. To renounce or reject with solemnity; to recant; to
      abandon forever; to reject; repudiate; as, to abjure
      errors. "Magic I here abjure." --Shak.
      [1913 Webster]

   Syn: See Renounce.
        [1913 Webster]

WordNet (r) 3.0 (2006):

abjure
    v 1: formally reject or disavow a formerly held belief, usually
         under pressure; "He retracted his earlier statements about
         his religion"; "She abjured her beliefs" [syn: abjure,
         recant, forswear, retract, resile]