Fabric-covered walls of library echo (5)
I believe the answer is:
reply
'echo' is the definition.
(I've seen this in another clue)
'fabric-covered walls of library' is the wordplay.
'fabric-covered' becomes 'rep' (I can't explain this - if you can you should believe this answer much more).
'walls of' suggests removing the centre (the external letters or walls of the word are used).
'library' with its middle removed is 'ly'.
'rep'+'ly'='REPLY'
Can you help me to learn more?
(Other definitions for reply that I've seen before include "counterattack?" , "Comeback" , "response is demanded" , "Return" , "Come back" .)