Unusually large composer (5)
I believe the answer is:
elgar
'composer' is the definition.
(Edward Elgar)
'unusually large' is the wordplay.
'unusually' indicates anagramming the letters.
'large' is an anagram of 'ELGAR'.
(Other definitions for elgar that I've seen before include "Glare strangely at the English composer" , "Scorer" , "Glare at composer of 'The Dream of Gerontius'" , "He scored" , "13 composer, 1857-1934" .)