The origin of the word 'Mafia' , and its derivative(s) 'Mafioso' etc. are disputed.
Etymology-online says :
The immediate source of mafioso, then, would be 19c. Sicilian mafiusu, "signifying a bully, arrogant but also fearless, enterprising, and proud" [Gambetta], who favors as the Arabic source an adjective from marfud "rejected."
Whereas, the 2009 book The Last Godfathers, John Follain, Hodder & Stoughton, states :
Even the origin of the word 'mafia' remains obscure. Some believe its roots lie in the Arab domination of Sicily from 827 to 1061 and the Arabic word mahias (daring) or Ma àfir (the name of a Saracen tribe).