1. to look angry or threatening; to frown or scowl
2. (of the sky or weather) to look dark, cloudy, or threatening
Usage: often used of weather or atmospheric conditions

Examples

• He loured at me across the table when I made the joke.
• The sky began to lour as the storm approached.
• She loured disapprovingly at the messy room.
• Dark clouds loured overhead, threatening rain.
• He loured in silence, clearly upset by the news.
• The weather loured all morning before the downpour began.