criminal vs vicious

criminal is a noun but vicious is not a noun.

Word	Noun	Adjective	Verb	Adverb
criminal	Yes	Yes	No	No
vicious	No	Yes	No	No

As adjectives, criminal and vicious are synonyms defined as:

Other synonyms of criminal include condemnable, deplorable, reprehensible.

criminal (noun)	vicious (noun)
someone who has committed a crime or has been legally convicted of a crime

criminal (adjective)	vicious (adjective)
guilty of crime or serious offense	(of persons or their actions) able or disposed to inflict pain or suffering
involving or being or having the nature of a crime	marked by deep ill will; deliberately harmful
bringing or deserving severe rebuke or censure	having the nature of vice
	bringing or deserving severe rebuke or censure