changeless vs unalterable

changeless and unalterable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
changeless	No	Yes	No	No
unalterable	No	Yes	No	No

As adjectives, changeless and unalterable are synonyms defined as:

changeless and unalterable: remaining the same for indefinitely long times

changeless (adjective)	unalterable (adjective)
not subject or susceptible to change or variation in form or quality or nature	not capable of being changed or altered
unvarying in nature	of a sentence; that cannot be changed
remaining the same for indefinitely long times	remaining the same for indefinitely long times