Having the lower incisor teeth projecting beyond the upperones, as in the bulldog.
The sight of a man(nude) from his back side while bent over, exposing his testicles and hairy anus. Typically occurs inadvertently while adult movies are being filmed at certain angles. A very disturbing and surprising image if not expected; adult films should be required to give a 5 second or longer warning prior to displaying an undershot.
* These videos are coming directly from Youtube, they may or may not be most relevant to the word "Undershot"