unrelenting vs brutal

unrelenting and brutal both are adjectives.

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

As adjectives, unrelenting and brutal are synonyms defined as:

unrelenting (adjective)	brutal (adjective)
never-ceasing	disagreeably direct and precise
not to be placated or appeased or moved by entreaty	resembling a beast; showing lack of human sensibility
punishingly harsh	punishingly harsh
	(of persons or their actions) able or disposed to inflict pain or suffering