1. Dark, misty and gloomy.
2. In Homestuck, the quadrant of love represented by a spade that stands for hate love
When a pair of adversaries delve into this quadrant, they become each other's KISMESIS. As one of the concupiscent quadrants, it plays a role in procreation as well. There is no particularly good human translation for this concept. The closest would be an especially potent arch-rivalry.
1. The room had a very caliginous aura to it
2. Our relationship is very caliginous, I would call her my kismesis.
2b. "I hate you" "I hate you too" *passionate making out*
A word or term meaning something along the lines of "bad, horrible, terrible" in an angry sense
"Dude that englisch exam was totally caliginous"