Convenient Haydn composition (5)
I believe the answer is:
handy
'convenient' is the definition.
('handy' can be similar in meaning to 'convenient')
'haydn composition' is the wordplay.
'composition' is an anagram indicator.
'haydn' anagrammed gives 'HANDY'.
(Other definitions for handy that I've seen before include "Accessible" , "Dexterous" , "quite useful" , "Convenient; skilful" , "Useful - competent" .)