relentless vs unrelenting

relentless and unrelenting both are adjectives.

Word	Noun	Adjective	Verb	Adverb
relentless	No	Yes	No	No
unrelenting	No	Yes	No	No

As adjectives, relentless and unrelenting are synonyms defined as:

Other synonyms of relentless include persistent.

As adjectives, relentless and unrelenting are synonyms defined as:

relentless and unrelenting: not to be placated or appeased or moved by entreaty

Other synonyms of relentless include grim, inexorable, stern, unappeasable, unforgiving.

relentless (adjective)	unrelenting (adjective)
never-ceasing	never-ceasing
not to be placated or appeased or moved by entreaty	not to be placated or appeased or moved by entreaty
	punishingly harsh