Deposit, exudation, wet, primarily (3)
I believe the answer is:
dew
This might be a double definition.
'deposit exudation' is the first definition.
'dew' can be an answer for 'deposit' (I've seen this before). I'm not sure about the 'exudation' bit.
'wet primarily' is the second definition.
'dew' can be an answer for 'wet' (moisture on the ground). I am not certain of the 'primarily' bit.
Can you help me to learn more?
(Other definitions for dew that I've seen before include "Night-time condensation" , "'The foggy, foggy - - ' (song)" , "Moisture on ground" , "Morning or evening condensation" , "The damp of early morning" .)