Wetness (8)
I believe the answer is:
moisture
'wetness' is the definition.
(I know that moisture is a type of wetness)
This is all the clue.
(Other definitions for moisture that I've seen before include "Diffused liquid such as vapour or condensation" , "Liquid in small quantity, in the air say" , "Liquid in vapour or spray form" , "Wetness caused by water" , "Slight wetness" .)