"The Merry Widow" composer (5)
I believe the answer is:
lehar
'the merry widow composer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lehar that I've seen before include "Austrian of note" , "Hungarian who composed" , "Operettist" , "He scored" , "Viennese composer" .)