May creak, but it's got a sound look (5)
I believe the answer is:
stair
'may creak' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'it's got a sound look' is the wordplay.
'it's got a sound' becomes 'st' (I can't justify this - if you can you should believe this answer much more).
'look' becomes 'air' (I've seen this before).
'st'+'air'='STAIR'
'but' is the link.
Can you help me to learn more?
(Other definitions for stair that I've seen before include "Word linking way and well" , "this could get one down" , "One of a flight of steps" , "Support on which to step" , "Rising step" .)