WordNet (r) 3.0 (2006):

mutant
    adj 1: tending to undergo or resulting from mutation; "a mutant
           gene"
    n 1: (biology) an organism that has characteristics resulting
         from chromosomal alteration [syn: mutant, mutation,
         variation, sport]
    2: an animal that has undergone mutation

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "mutant":
   altered, avatar, better, catabolism, catalysis, changeable,
   changed, consubstantiation, converted, degenerate, deviant,
   displacement, divergent, heterotopia, improved, metabolism,
   metagenesis, metamorphism, metamorphosed, metamorphosis,
   metastasis, metastasized, metathesis, metempsychosis, modified,
   mutated form, mutation, permutation, qualified, rebuilt, reformed,
   reincarnation, renewed, revived, revolutionary, sport, subversive,
   transanimation, transfiguration, transfigurement, transformation,
   transformed, transformism, translated, translation, translocation,
   transmigration, transmogrification, transmutation, transmuted,
   transposition, transubstantiation, unmitigated, worse



The Free On-line Dictionary of Computing (30 December 2018):

mutant

    Microsoft's term for a mutex which is
   generally used in user mode but can also be used in kernel
   mode.  According to this terminology a mutex is only used in
   kernel mode.

   ["Microsoft Windows NT Workstation Resource Kit"].

   (1997-07-30)