begloom means to make gloomy; darken. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Etymology
From be- + gloom.
verb
- To make gloomy; darken.
- To sadden.“No cold can chill them, and no fire consume
No light can daze, no darkness can begloom
Nor blank vacuity 'twixt orb and orb”