gaolbird vs felon

gaolbird and felon both are nouns.

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

As nouns, felon is a hypernym of gaolbird; that is, felon is a word with a broader meaning than gaolbird:

gaolbird: a criminal who has been jailed repeatedly
felon: someone who has committed a crime or has been legally convicted of a crime

Other hypernyms of gaolbird include criminal, crook, malefactor, outlaw.

gaolbird (noun)	felon (noun)
a criminal who has been jailed repeatedly	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