Mafia likely derives from the Arabic marfūd meaning rejected.

Evidence

The term may well have come from Arabic. The original candidate was mahyas, “braggart”; but Lo Monaco (1990) proposes the more plausible marfūd, “rejected.” This adjective would have evolved into mafiusu or maffiusu in Sicilian dialect through combination with a similar-sounding term, marpiuni or marfiuni, found throughout Italy (and in contemporary Italian as marpione), meaning an astute impostor. This explanation is supported by a series of related terms (marfuzin Spanish, malfusso in early Tuscan, marfusu in Sicilian, mafiun in Piedmontese) and by conceivable phonological modifications (rf = lf = ff, u = iu). In reference to a man, mafiusu in nineteenth-century Sicily was ambiguous, signifying a bully, arrogant but also fearless, enterprising, and proud. — Diego Gambetta, The Sicilian Mafia The Business of…, 352

Categorization

• DEFINE: Covers the etymological chain from Arabic marfūd through Sicilian dialect to the modern term.
• QUESTION: The ambiguous nineteenth-century meaning (bully vs. fearless/enterprising/proud) is worth chasing — that semantic tension may be load-bearing for how the brand attached to the organization.