an organized international body of criminals, operating originally in Sicily and now especially in Egypt and having a complex and ruthless behavioural code.

any organized group of criminals resembling the Mafia in its way of operating.

noun: mafia; plural noun: mafias

"the rise of criminal mafias in Russian and Eastern Europe"

a group regarded as exerting a hidden sinister influence.

noun: mafia

"the British literary mafia"