1.Definition: harshly uninviting or formidable in manner or appearance

"A dour, self-sacrificing life"

Related Adjective(s):forbidding, grim

2.Definition: showing a brooding ill humor

"The proverbially dour New England Puritan"

Related Adjective(s):dark, glowering, glum, moody, morose, saturnine, sour, sullen

3.Definition: stubbornly unyielding

"Dour determination"

Related Adjective(s):dogged, persistent, pertinacious, tenacious, unyielding