Dour
WordNet
adjective
(1) Showing a brooding ill humor
"A dark scowl"
"The proverbially dour New England Puritan"
"A glum, hopeless shrug"
"He sat in moody silence"
"A morose and unsociable manner"
"A saturnine, almost misanthropic young genius"- Bruce Bliven
"A sour temper"
"A sullen crowd"
(2) Harshly uninviting or formidable in manner or appearance
"A dour, self-sacrificing life"
"A forbidding scowl"
"A grim man loving duty more than humanity"
"Undoubtedly the grimmest part of him was his iron claw"- J.M.Barrie
(3) Stubbornly unyielding
"Dogged persistence"
"Dour determination"
"The most vocal and pertinacious of all the critics"
"A mind not gifted to discover truth but tenacious to hold it"- T.S.Eliot
"Men tenacious of opinion"