leftster Share definition Flag A leftist hipster especially the obnoxious socialist kind who does pay taxes, accepts responsibility, and complains about the economy not suiting his or her needs. A leftster is totally insane and whines about Obama not having a third term. leftster by Yobberson July 13, 2017 0 0 Get merch Get the leftster mug. Buy Now — $32.95 See more merch