unrelenting vs unforgiving

unrelenting and unforgiving both are adjectives.

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

As adjectives, unrelenting and unforgiving are synonyms defined as:

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

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

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