It's depressing for a listener surrounded by what's uninteresting (6)
I believe the answer is:
dreary
'it's depressing' is the definition.
(I've seen this in another clue)
'listener surrounded by what's uninteresting' is the wordplay.
'listener' becomes 'ear' (body part which hears or listens).
'surrounded by' means one lot of letters goes inside another.
'what's uninteresting' becomes 'dry' (dry can mean dull or boring).
'ear' put into 'dry' is 'DREARY'.
'for a' acts as a link.
(Other definitions for dreary that I've seen before include "routine" , "Dark" , "Grey and dull" , "Bleak, depressing" , "Dismal, depressing" .)