Spray gun (5,6)
I believe the answer is:
water pistol
'spray gun' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'spray gun' is the wordplay.
'spray' becomes 'water' (I've seen this in another clue).
'gun' becomes 'pistol' (pistol is a kind of gun).
'water'+'pistol'='WATER-PISTOL'
Can you help me to learn more?
(Other definitions for water pistol that I've seen before include "harmless weapon?" , "Plaything" , "Source of aggressive jet" , "Toy firearm" , "Toy weapon" .)