WordNet (r) 3.0 (2006):

die hard
    v 1: continue to exist; "These stories die hard"; "The legend of
         Elvis endures" [syn: prevail, persist, die hard,
         run, endure]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "die hard":
   backward, balk, be determined, be in earnest, be resolved,
   buckle down, buckle to, conservative, cross the Rubicon,
   die fighting, die game, die in harness, fogyish, go for broke,
   hold out, mean business, never say die, nonprogressive,
   not back down, not budge, not give up, not submit, old-fashioned,
   old-fogyish, old-line, opposed to change, orthodox, persevere,
   preservative, reactionary, reactionist, remain firm, right,
   right of center, right-wing, stand fast, stand out, stand pat,
   standpat, stay it out, stick, stick fast, stick it out, stickle,
   take no denial, take the plunge, tory, traditionalistic,
   ultraconservative, unprogressive