Damp fog gathers round (5)
I believe the answer is:
moist
'damp' is the definition.
(I know that damp can be written as moist)
'fog gathers round' is the wordplay.
'fog' becomes 'mist' (synonyms).
'gathers' means one lot of letters goes inside another.
'round' becomes 'o' (round can mean a round object).
'mist' going around 'o' is 'MOIST'.
(Other definitions for moist that I've seen before include "bit wet" , "Damp or clammy" , "Slightly wet, damp" , "lubricated" , "Affected by tears, perhaps" .)