Enigmatic composer (5)
I believe the answer is:
elgar
'composer' is the definition.
(Edward Elgar)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for elgar that I've seen before include "Composer of Pomp and Circumstance marches, d. 1934" , "He scored" , "Enigma Vars. composer" , "Glare critically at the British composer" , "Glare strangely at the English composer" .)