Source : Webster's Revised Unabridged Dictionary (1913)

Underpitch \Un`der*pitch"\, v. t. [imp. {Underpight}.] [OE.
   underpicchen. See {Under}, and {Pitch} to throw, fix.]
   To fill underneath; to stuff. [Obs.]

         He drank and well his girdle underpight. --Chaucer.