immutable(-ility)

Concise Bible Dictionary:

Strong’s Dictionary of Greek Words:

Greek:
ἀμετάθετος
Transliteration:
ametathetos
Phonic:
am-et-ath’-et-os
Meaning:
from 1 (as a negative particle) and a derivative of 3346; unchangeable, or (neuter as abstract) unchangeability
KJV Usage:
immutabl e(-ility)

From Anstey’s Doctrinal Definitions: