stiffy killer Share definition Flag A girl so ugly that she immediately deflates a perfectly good hard-on by simply looking at you. Things were going good at the party until, Rita brought her stiffy killer friend Bertha, and it was all down hill from there. stiffy killer by J.B. Trevor March 17, 2008 0 0 Get merch Get the stiffy killer mug. Buy Now — $32.95 See more merch