n argument; fight. This is certainly rhyming slang, but no one’s sure of whence it came. It could either be “Barney Rubble” / “trouble” (Barney Rubble is a character in the cartoon “The Flintstones”), or “Barn Owl” / “row” (when it means “fight,” “row” rhymes with “now”). The latter is marginally more likely, as “trouble” could be many things other than a fight, but the former is a more popular explanation. Pick one.