An offensive Cockney rhyming slang for "Jock," itself an offensive slang word or term of address for a Scottish person (derived from the Scottish variant for the name "Jack"). Primarily heard in UK. Oy, sweaty sock! Why don't you move back north and leave our jobs alone! The opposition keeps calling us sweaty socks to invalidate our call for Scottish independence.
See also: sock
n. an athlete; a jock. (Usually plural.) I live in a dorm with a bunch of sweat socks. They feed us well, anyway.