felonious vs criminal

felonious is not a noun while criminal is a noun.

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

As adjectives, felonious and criminal are synonyms defined as:

felonious and criminal: involving or being or having the nature of a crime

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

felonious (adjective)	criminal (adjective)
involving or being or having the nature of a crime	guilty of crime or serious offense
	involving or being or having the nature of a crime
	bringing or deserving severe rebuke or censure