Source : Webster's Revised Unabridged Dictionary (1913)

Underwork \Un`der*work"\, v. t. [imp. & p. p. {Underworked}or
   {Underwrought}; p. pr. & vb. n. {Underworking}.]
   1. To injure by working secretly; to destroy or overthrow by
      clandestine measure; to undermine.

            But thou from loving England art so far, That thou
            hast underwrought his lawful king.    --Shak.

   2. To expend too little work upon; as, to underwork a
      painting. --Dryden.

   3. To do like work at a less price than; as, one mason may
      underwork another.