/ fɒg; NAmE fɔːg; fɑːg/ noun , verb
■ noun [ U , C ]
1.
a thick cloud of very small drops of water in the air close to the land or sea, that is very difficult to see through :
Dense / thick fog is affecting roads in the north and visibility is poor.
freezing fog
Patches of fog will clear by mid-morning.
We get heavy fogs on this coast in winter.
The town was covered in a thick blanket of fog .
The fog finally lifted (= disappeared) .
—compare mist
2.
a state of confusion, in which things are not clear :
He went through the day with his mind in a fog .
■ verb ( -gg- )
1.
[ v , vn ] fog (sth) (up) if a glass surface fogs or is fogged up, it becomes covered in steam or small drops of water so that you cannot see through
2.
[ vn ] to make sb/sth confused or less clear :
I tried to clear the confusion that was fogging my brain.
The government was trying to fog the real issues before the election.
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WORD ORIGIN
mid 16th cent.: perhaps a back-formation from foggy .