Point duet out as piece of music (5)
I believe the answer is:
etude
'piece of music' is the definition.
(etude is a kind of piece of music)
'point duet out' is the wordplay.
'point' becomes 'e' (compass point).
'out' is an anagram indicator (out can mean wrong or inaccurate).
'duet' is an anagram of 'tude'.
'e'+'tude'='ETUDE'
'as' acts as a link.
(Other definitions for etude that I've seen before include "bit of practice" , "Short piece of music for solo instrument" , "short musical piece" , "Indian statesman" , "Noted composition" .)