L.S. Share definition Flag L.S. stands for low shit. usually something embarrasing that you're supposed to keep on the low, but shit you gotta let it out and tell the world!!! L.S.!!!! that boy took a shit on himself in class last week. L.S. by nigga_frmthaeast October 4, 2009 0 0 Get merch Get the L.S. mug. Buy Now — $32.95 See more merch