Clouded (6)
'clouded' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for opaque that I've seen before include "Obscure" , "Without lustre" , "Dark" , "Not translucent" , "Not allowing light to pass through" .)
(Other definitions for turbid that I've seen before include "Dense, thick and cloudy" , "Muddy, murky, cloudy" , "Murky, clouded" , "(Of liquid) cloudy" , "Disordered" .)