SemiGab Share definition Flag (verb, adjective, noun) To act in a retarded way and be overly proud of it... At a family supper, he stood up and semiGabed by leaving abruptly and shouting "fuck youuuuuu!!" for no apparent reason. SemiGab by Bhoriss Viahn May 9, 2018 0 0 Get merch Get the SemiGab mug. Buy Now — $32.95 See more merch