unremitting vs never-ending

unremitting and never-ending both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unremitting	No	Yes	No	No
never-ending	No	Yes	No	No

As adjectives, unremitting and never-ending are synonyms defined as:

unremitting and never-ending: uninterrupted in time and indefinitely long continuing

Other synonyms of unremitting include ceaseless, constant, incessant, perpetual, unceasing.

unremitting (adjective)	never-ending (adjective)
uninterrupted in time and indefinitely long continuing	uninterrupted in time and indefinitely long continuing