criminal vs felon

criminal and felon both are nouns.

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

As nouns, criminal and felon are synonyms defined as:

criminal and felon: someone who has committed a crime or has been legally convicted of a crime

Other synonyms of criminal include crook, malefactor, outlaw.

criminal (noun)	felon (noun)
someone who has committed a crime or has been legally convicted of a crime	someone who has committed a crime or has been legally convicted of a crime
	a purulent infection at the end of a finger or toe in the area surrounding the nail

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