incommutable

from WordNet (r) 3.0 (2006)

incommutable
    adj 1: not subject to alteration or change [ant: {commutable}]
    2: not interchangeable or able to substitute one for another; "a
       rare incommutable skill"

from The Collaborative International Dictionary of English v.0.48

Incommutable \In`com*mut"a*ble\, a. [L. incommutabilis: cf. F.
   incommutable. See {In-} not, and {Commutable}.]
   Not commutable; not capable of being exchanged with, or
   substituted for, another. --Cudworth. --
   {In`com*mut"a*ble*ness}, n. -- {In`com*mut"a*bly}, adv.
   Incompact

from Moby Thesaurus II by Grady Ward, 1.0

33 Moby Thesaurus words for "incommutable":
      changeless, constant, immutable, inconvertible, indefeasible,
      inert, insusceptible of change, intransmutable, invariable,
      irretrievable, irreversible, irrevocable, lasting, noble,
      nonreturnable, nonreversible, permanent, reverseless, unalterable,
      unalterative, unaltered, unchangeable, unchanged, unchanging,
      undeflectable, undeviating, unmodifiable, unremitting,
      unrestorable, unreturnable, unsusceptible, unvariable, unvarying

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