Haze not seen, we hear (4)
I believe the answer is:
mist
'haze' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for mist that I've seen before include "Fine spray" , "Mizzle; light rain" , "low-level cloud" , "Cloud; thin fog" , "Haze" .)