satanic vs fiendish

satanic and fiendish both are adjectives.

Word	Noun	Adjective	Verb	Adverb
satanic	No	Yes	No	No
fiendish	No	Yes	No	No

As adjectives, satanic and fiendish are synonyms defined as:

satanic and fiendish: extremely evil or cruel; expressive of cruelty or befitting hell

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

satanic (adjective)	fiendish (adjective)
extremely evil or cruel; expressive of cruelty or befitting hell	extremely evil or cruel; expressive of cruelty or befitting hell