Cloudy means with the sky covered in grey and white. A cloudy day, cloudy with sunny intervals, mostly cloudy.
British forecasts grade it carefully: cloudy, mostly cloudy, cloudy with sunny intervals, and overcast, which is complete cover. Of a liquid, cloudy means not clear: cloudy water, cloudy apple juice, which in juice is a selling point and in water is not. Note cloud, and every cloud has a silver lining; and that cloudy judgement means unclear thinking rather than anything meteorological.
1adjectivecloudyWith the sky covered in grey and white.
“It was cloudy all morning, but the sun came out after lunch.”
synonyms: overcast, grey
2adjectiveclearNot clear, of a liquid.
“The water in the pond had turned cloudy and green.”
cloudy is a quality of cover or clarity.
Also accepted in games: overcast
Middle English cloudy meant rocky before it meant overcast, because Old English clud meant a mass of rock. A cloud was named for looking like a hill in the sky, and the rock sense has entirely gone.
Old English
clūdiġ — stony, rocky
Middle English
cloudy — cloudy, overcast, gloomy, dark", also "hilly, rocky
English, today
cloudy
From Middle English cloudy (“cloudy, overcast, gloomy, dark", also "hilly, rocky”), from Old English clūdiġ (“stony, rocky”), equivalent to cloud + y.
Etymology from Wiktionary, CC BY-SA