Sicilian vs mafioso

Sicilian and mafioso both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sicilian	Yes	Yes	No	No
mafioso	Yes	No	No	No

As nouns, mafioso is a hyponym of Sicilian; that is, mafioso is a word with a more specific, narrower meaning than Sicilian:

Sicilian (noun)	mafioso (noun)
a resident of Sicily	a member of the Mafia crime syndicate in the United States
	a member of the Sicilian Mafia

Sicilian (adjective)	mafioso (adjective)
of or relating to or characteristic of Sicily or the people of Sicily