diabolical vs unholy

diabolical and unholy both are adjectives.

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

As adjectives, diabolical and unholy are synonyms defined as:

diabolical and unholy: extremely evil or cruel; expressive of cruelty or befitting hell

Other synonyms of diabolical include demonic, diabolic, fiendish, hellish, infernal, satanic.

diabolical (adjective)	unholy (adjective)
extremely evil or cruel; expressive of cruelty or befitting hell	not hallowed or consecrated
showing the cunning or ingenuity or wickedness typical of a devil	extremely evil or cruel; expressive of cruelty or befitting hell
	having committed unrighteous acts