The Collaborative International Dictionary of English v.0.48:

Dormy \Dor"my\, a. [Origin uncertain.] (Golf)
   Up, or ahead, as many holes as remain to be played; -- said
   of a player or side.

   Note: A player who is dormy can not be beaten, and at the
         worst must halve the match. --Encyc. of Sport.
         [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

dormy
    adj 1: in match play a side that stands as many holes ahead as
           there are holes remaining to be played; "he was dormie
           three and still lost the match" [syn: dormie, dormy]