dour (rhymes with tour; DOU-uhr)
adjective: sullen; severe; gloomy; stubborn
Probably from Latin durus (hard).
Earliest documented use: 1425
Usage (from Wordsmith)
“Though Herman Van Rompuy is characterised as ascetic, even dour, by nature, allies point to his penchant for crafting haiku, the seventeen-syllable Japanese poems, as evidence of a lighter side.”
Stanley Pignal; Lesser Light Respected as Skilled Mediator; Financial Times (London, UK); Nov 7, 2009.