change - undergo a change; become different in essence; losing one's or its original nature; "She changed completely as she grew older"; "The weather changed last night"

blacken out, black out - darken completely; "The dining room blackened out"

cloud over, cloud up, overcloud - become covered with clouds; "The sky clouded over"

change intensity - increase or decrease in intensity

maculate, tarnish, defile, sully, stain - make dirty or spotty, as by exposure to air; also used metaphorically; "The silver was tarnished by the long exposure to the air"; "Her reputation was sullied after the affair with a married man"

alter, change, modify - cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue"

embrown - cause to darken

murk - make dark, dim, or gloomy

dun - make a dun color

blind, dim - make dim by comparison or conceal

dim - make dim or lusterless; "Time had dimmed the silver"

bedim, benight, obscure - make difficult to perceive by sight; "The foliage of the huge tree obscures the view of the lake"

cloud, overcast - make overcast or cloudy; "Fall weather often overcasts our beaches"