LNSTD Share definition Flag Variation of LNBC. A late night booty call with an especially promiscuous girl with an increased possibility of catching a STD. How drunk were you? I can believe you had a LNSTD with her. better get your junk checked out. LNSTD by fawnlnfun May 11, 2009 0 0 Get merch Get the LNSTD mug. Buy Now — $32.95 See more merch