Longman Dictionary of Contemporary English - fog

~1 n 1 cloudy air near the ground which is difficult to see through  (Thick fog is making driving conditions hazardous. | fog bank (=a large area of fog))  (- compare mist1 (1)) 2 in a fog informal confused and unable to think clearly  (Sorry, what did you say? - my mind's in a fog at the moment.) ~2 v fogged, fogging 1 if something made of glass fogs up or becomes fogged up, it becomes covered in small drops of water that make it difficult to see through 2 fog the issue to make a subject, problem etc become unclear and more complicated  (I think we're just fogging the issue by looking at all these details.)