unforgiving vs vengeful

unforgiving and vengeful both are adjectives.

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

unforgiving (adjective)	vengeful (adjective)
unwilling or unable to forgive or show mercy	disposed to seek revenge or intended for revenge
not to be placated or appeased or moved by entreaty