Idioms and Phrases with cloud over
Also, cloud up.
Become overcast with clouds, as in It's clouding over now, so it may rain soon, or It was too hot and sunny, but after a while the sky clouded up and we ventured outside. [Mid-1700s]
Become opaque, misty, or dim, as in I'm sweating so much that my eyeglasses are clouded over.