[a-riv] Share definition Flag a slang term for some one very annoying, other known as. a. annoying. riv. i wanna throw him in the river. kid: "yo, how do you like that new kid?" you: " not at all, he's a total a-riv." [a-riv] by slangslinger October 18, 2008 0 0 Get merch Get the [a-riv] mug. Buy Now — $32.95 See more merch