(third-person singular simple present lours, present participle louring, simple past and past participle loured)
- (intransitive) To be dark, gloomy, and threatening, as clouds; to be covered with dark and threatening clouds, as the sky; to show threatening signs of approach, as a tempest.
- (intransitive) To frown; to look sullen.
From Middle English lour (“sad or frowning countenance"), louren (“to frown or scowl; to be dark or overcast; look askant, mistrust; wither, fade, droop; lurk, skulk"), Old English lowren, luren. Compare Dutch loeren, German lauern (“lurk, be on the watch"), and English leer and lurk.