buh Share definition Flag derived from the word "Buh Bye". Meaning, cya, peace, out, later, one etc. Can also be used in a dissapproving manner. "yo, i'm out, BUH" "this homework is too hard, BUH" buh by Jon Lines February 26, 2005 0 0 Get merch Get the buh mug. Buy Now — $32.95 See more merch