The Collaborative International Dictionary of English v.0.48:

Underdo \Un`der*do"\, v. i.
   To do less than is requisite or proper; -- opposed to
   overdo. --Grew.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Underdo \Un`der*do"\, v. t.
   To do less thoroughly than is requisite; specifically, to
   cook insufficiently; as, to underdo the meat; -- opposed to
   overdo.
   [1913 Webster]