Overcast (6)
'overcast' is the definition.
(I know that cloudy is a overcast)
This is all the clue.
(Other definitions for cloudy that I've seen before include "'Overcast, nebulous (6)'" , "It's unclear" , "Not transparent" , "Obscure" , "Murky or nebulous" .)
'overcast' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for grey that I've seen before include "Dismal - colour" , "The colour of ash" , "9 colour" , "(Of weather) dull, cloudy" , "Bushy-tailed North America rodent, now a UK pest" .)
(Other definitions for gray that I've seen before include "Author of ballad opera" , "Elegiac poet" , "a bit gloomy for the Americans" , "Thomas --, poet" , "Midway between white and black" .)
'overcast' is the definition.
(I know that overcast can be written as sunless)
This is all the clue.
(Other definitions for sunless that I've seen before include "gloomy" , "Unlit by solar light" , "dim, certainly not bright" , "Dull" , "dark" .)