It's a colloquial pronunciation of "rum one"

"rum" in this sense meaning not the drink but something like "odd." It can actually cover a wide range of oddness, from mere eccentricity to criminal behaviour. The OED gives some examples but doesn't offer any etymology, the American Heritage Dictionary suggests that it may come from "rom" a gypsy. In any case, I think the spelling would be "rum un."

i didn't know all of this by the way, i just copied off of on the internet

Posted By: Tombs, Sep 14, 17:32:01