Key cut out of pipe (4)
I believe the answer is:
duct
'pipe' is the definition.
(I've seen this in another clue)
'key cut out' is the wordplay.
'key' becomes 'd' (musical key).
'out' indicates an anagram (out can mean wrong or inaccurate).
'cut' is an anagram of 'uct'.
'd'+'uct'='DUCT'
'of' acts as a link.
(Other definitions for duct that I've seen before include "Pipe, tube" , "Tube for cables, air, etc" , "Enclosed conduit for fluid" , "Air passage" , "Channel" .)