Definition of "lour" in English

verb

1. (intransitive) To frown; to look sullen.

2. (intransitive, figuratively) To be dark, gloomy, and threatening, as clouds; of the sky: to be covered with dark and threatening clouds; to show threatening signs of approach, as a tempest.

noun

1. A frown, a scowl; an angry or sullen look.

2. (figuratively) Of the sky, the weather, etc.: a dark, gloomy, and threatening appearance.