unalterable vs inalterable

unalterable and inalterable both are adjectives.

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

As adjectives, unalterable and inalterable are synonyms defined as:

unalterable (adjective)	inalterable (adjective)
not capable of being changed or altered	not capable of being changed or altered
of a sentence; that cannot be changed
remaining the same for indefinitely long times