also: まるぼう
noun
yakuza group; organized crime syndicate
Police and media slang for a yakuza organization. The マル (maru) is a code prefix used by law enforcement to denote organized crime, and 暴 is short for 暴力団 (bōryokudan, 'violent group').
See also: 暴力団
警察はマル暴の事務所を捜索した。
The police searched the yakuza group's office.
あの事件にはマル暴が絡んで
It seems that a yakuza group is involved in that incident.
Abbreviation of マル (police code prefix for organized crime) + 暴 (from 暴力団, 'violent group'). The exact origin of the マル code is uncertain, but it is widely used in Japanese law enforcement to designate yakuza-related matters.