intransigent
     adj : not capable of being swayed or diverted from a course;
           unsusceptible to persuasion; "he is adamant in his
           refusal to change his mind"; "Cynthia was inexorable;
           she would have none of him"- W.Churchill; "an
           intransigent conservative opposed to every liberal
           tendancy" [syn: {adamant}, {adamantine}, {inexorable}]
Source: WordNet® 2.0