certain, changeless, constant, fated, fateful, immutable, inalienable, incommunicable, incommutable, inconvertible, ineluctable, inert, inescapable, inevasible, inevitable, inexorable, inflexible, insusceptible of change, intransmutable, invariable, irresistible, irretrievable, irreversible, irrevocable, lasting, necessary, noble, noncommunicable, noncontagious, noninfectious, nonreturnable, nonreversible, permanent, relentless, resistless, reverseless, sure, sure as death, sure as fate, unalterable, unalterative, unaltered, unavoidable, unchangeable, unchanged, unchanging, uncontrollable, undeflectable, undeviating, unimpartable, unmodifiable, unpreventable, unremitting, unrestorable, unreturnable, unstoppable, unsusceptible, unvariable, unvarying, unyielding