Not mutable; not capable or susceptible of change; unchangeable; unalterable. That by two immutable things, in which it was impossible for god to lie, we might have a strong consolation. (Heb. Vi. 18) Immutable, immortal, infinite, Eternal king. (Milton)
Origin: L. Immutabilis; pref. Im- not – mutabilis mutable. See Mutable.