Listener in home that's most closely related (7)
I believe the answer is:
nearest
'most closely related' is the definition.
(I've seen this before)
'listener in home' is the wordplay.
'listener' becomes 'ear' (body part which hears or listens).
'in' is an insertion indicator.
'home' becomes 'nest' (a bird's home).
'ear' going within 'nest' is 'NEAREST'.
'that's' is the link.
(Other definitions for nearest that I've seen before include "Close family members" , "With dearest, they're our loved ones" , "Most closely related" , "Most intimate" , "Most accessible" .)