also: マルそう
noun
Police slang for a biker gang, especially associated with 暴走族 (bōsōzoku). Used in law enforcement contexts.
See also: 暴走族
昨夜、丸走のメンバーが検挙された。
Last night, members of a biker gang were arrested.
警察は丸走の取り締まりを強化している。
The police are cracking down on biker gangs.
暴走族 is the standard term for biker gangs; 丸走 is police slang for the same group.
Police slang; the exact derivation is uncertain, but 丸 may be a code or abbreviation used in law enforcement, and 走 refers to running or driving.