unhallowed vs unholy

unhallowed and unholy both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unhallowed	No	Yes	No	No
unholy	No	Yes	No	No

As adjectives, unhallowed and unholy are synonyms defined as:

unhallowed (adjective)	unholy (adjective)
not hallowed or consecrated	not hallowed or consecrated
	extremely evil or cruel; expressive of cruelty or befitting hell
	having committed unrighteous acts