WordWeb Online

1. Incapable of being repudiated or transferred to another
   "endowed by their Creator with certain inalienable rights";
   - unalienable
    
2. Not subject to forfeiture
   "an inalienable right";
   - unforfeitable

See also: absolute, indefeasible, infrangible, intrinsic, intrinsical, inviolable, non-negotiable, nontransferable, unassignable, untransferable

Antonym: alienable

Encyclopedia: Inalienable