"A Life For The Czar" composer (6)
I believe the answer is:
'a life for the czar composer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for glinka that I've seen before include "Russian composer (Ruslan and Ludmilla)" , "Russian composer (A Life for the Tsar)" , "Russian composer, d. 1857" .)