gangdom vs Maffia

gangdom and Maffia both are nouns.

Word	Noun	Adjective	Verb	Adverb
gangdom	Yes	No	No	No
Maffia	Yes	No	No	No

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

gangdom: underworld organizations
Maffia: a secret terrorist group in Sicily; originally opposed tyranny but evolved into a criminal organization in the middle of the 19th century

Other hyponyms of gangdom include yakuza, Mafia, Sicilian Mafia, Black Hand, Camorra, crime syndicate, family, mob, syndicate.

gangdom (noun)	Maffia (noun)
underworld organizations	a crime syndicate in the United States; organized in families; believed to have important relations to the Sicilian Mafia
	a secret terrorist group in Sicily; originally opposed tyranny but evolved into a criminal organization in the middle of the 19th century