Northern listener close by (4)
I believe the answer is:
near
'close by' is the definition.
(near means close by)
'northern listener' is the wordplay.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'listener' becomes 'ear' (body part which hears or listens).
'n'+'ear'='NEAR'
(Other definitions for near that I've seen before include "Not far distant in time or space etc." , "A short distance away" , "unlikely to spend much?" , "(Get) close to" , "Easy to reach - hard to touch!" .)