Throw water on (5)
I believe the answer is:
'throw water on' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for douse that I've seen before include "Throw water over, extinguish" , "Smother with water" , "Drench; extinguish" , "Of fire, quench with water" , "can make you really wet" .)