Listener, therefore, is made of clay (7)
I believe the answer is:
earthen
'made of clay' is the definition.
(I've seen this in another clue)
'listener therefore' is the wordplay.
'listener' becomes 'ear' (body part which hears or listens).
'therefore' becomes 'then' (I've seen this in another clue).
'ear'+'then'='EARTHEN'
'is' is the link.
(Other definitions for earthen that I've seen before include "(Of a pot) made of fired clay" , "that's thrown in clay" , "Made of baked clay, perhaps ware" , "(Of pot) made of baked clay" , "Made of baked or fired clay" .)