undershot

1. participlepastsimple past and past participle of undershoot

1. not comparablePowered by water flowing from below. (of a water wheel)
2. not comparablebiologyHaving the lower incisor teeth projecting beyond the upper ones, as in the bulldog.

   His blunt undershot mouth curved in a smile that was somewhat ingratiating.

   1931, Dashiell Hammett, chapter 3, in The Glass Key, New York: Vintage, published 1972, page 50

plural undershots

1. An undershot water wheel.