Liquid in vapour or spray form (8)
I believe the answer is:
moisture
'liquid in vapour or spray form' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for moisture that I've seen before include "Diffused liquid such as vapour or condensation" , "Wetness caused by water" , "Small amount of liquid that causes dampness" , "Small amount of liquid causing dampness" , "Slight wetness" .)