Axes cut perfect instrument (9)
I believe the answer is:
xylophone
'instrument' is the definition.
(xylophone is a kind of instrument)
'axes cut perfect' is the wordplay.
'axes' becomes 'xy' (x axis and y axis).
'cut' becomes 'lop' (lopping is a kind of cutting**).
'perfect' becomes 'hone' ('hone' can be a synonym of 'perfect').
'xy'+'lop'+'hone'='XYLOPHONE'
(Other definitions for xylophone that I've seen before include "Musical instrument with bars" , "Instrument with wooden bars to be struck" , "Percussion instrument played with mallet" , "Patrick Moore's instrument" , "Oxyphenol (anag.)" .)