Godan verb with 'ru' ending, Intransitive verb

to get cloudy; to cloud over; to become overcast

to cloud up; to fog up; to mist up; to become dim

to be gloomy; to be clouded (expression); to be downcast

to look slightly downward (of a noh mask; indicating sadness, grief, etc.)

from 面曇るsee 照るsee てる・2