Giant of Baroque music (4)
I believe the answer is:
bach
'giant of baroque music' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bach that I've seen before include "Affectionate address" , "Musical family" , "Johann Sebastian . . . . , great composer (4)" , "J. S. -, Ger. composer" , "J. S. --, baroque composer" .)