US port dispersed fog (6)

I believe the answer is:

stupor

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'fog' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Maybe you can see an association between them that I don't see?

'us port dispersed' is the wordplay.
'dispersed' indicates anagramming the letters.
'us'+'port'='usport'
'usport' with letters rearranged gives 'STUPOR'.

Can you help me to learn more?

(Other definitions for stupor that I've seen before include "Shocked or drunken state" , "Mental torpor" , "Insensible state" , "lethargic" , "A state of coma or drowsiness" .)

I've seen this clue in the Sydney Morning Herald.

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