unforgiving vs unrelenting

unforgiving and unrelenting both are adjectives.

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

As adjectives, unforgiving and unrelenting are synonyms defined as:

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

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

unforgiving (adjective)	unrelenting (adjective)
unwilling or unable to forgive or show mercy	never-ceasing
not to be placated or appeased or moved by entreaty	not to be placated or appeased or moved by entreaty
	punishingly harsh