From The Collaborative International Dictionary of English v.0.48:
Immutable \Im*mu"ta*ble\, a. [L. immutabilis; pref. im- not +
mutabilis mutable. See Mutable.]
Not mutable; not capable or susceptible of change;
unchangeable; unalterable.
[1913 Webster]
That by two immutable things, in which it was
impossible for God to lie, we might have a strong
consolation. --Heb. vi. 18.
[1913 Webster]
Immutable, immortal, infinite,
Eternal King. --Milton.
-- Im*mu"ta*ble*ness, n. -- Im*mu"ta*bly, adv.
[1913 Webster]