The Collaborative International Dictionary of English v.0.48:

noninheritable \noninheritable\ adj.
   not capable of transmission by heredity. Opposite of
   inheritable. [Narrower terms: acquired, nurtural;
   congenital, inborn, innate]

   Syn: nonheritable, nonhereditary, nontransmissible.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

noninheritable
    adj 1: not inheritable [syn: noninheritable, nonheritable]
           [ant: heritable, inheritable]