Dead Betsy Share definition Flag A girl who lies still as if dead during sex, and lets the guy do all of the work. "Dude - I though that girl was going to be an amazing lay, but she turned out to be a dead betsy!" Dead Betsy by B.D. Smith November 6, 2007 0 0 Get merch Get the Dead Betsy mug. Buy Now — $32.95 See more merch