Sibelius, for one (4)
I believe the answer is:
finn
'sibelius for one' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for finn that I've seen before include "Twain's Huck; Trollope's Phineas" , "Sibelius, perhaps" , "Trollope's Phineas; one from Tampere" , "Northern European" , "EU statesman" .)