WordWeb Online

1. Harshly uninviting or formidable in manner or appearance
   "a dour, self-sacrificing life";
   - forbidding, grim
    
2. Showing a brooding ill humour
   "the proverbially dour New England Puritan";
   - dark, glowering, glum, moody, morose, saturnine, sour, sullen
    
3. Stubbornly persisting, refusing to give up
   "dour determination";
   - dogged, persistent, pertinacious, tenacious, unyielding

Derived forms: dourest, dourer

See also: ill-natured, obstinate, stubborn, unpleasant, unregenerate

Encyclopedia: Dour