Huge composition of Elgar (5)
I believe the answer is:
large
'huge' is the definition.
('large' can be similar in meaning to 'huge')
'composition of elgar' is the wordplay.
'composition of' is an anagram indicator (I've seen this in other clues).
'elgar' anagrammed gives 'LARGE'.
(Other definitions for large that I've seen before include "Wide-ranging" , "At which criminals possibly are free" , "Strapping" , "Big - 5 down (anag)" , "Extensive" .)