Whingers upset composer (8)
I believe the answer is:
gershwin
'composer' is the definition.
(George Gershwin, 1898-1937)
'whingers upset' is the wordplay.
'upset' indicates anagramming the letters.
'whingers' is an anagram of 'GERSHWIN'.
(Other definitions for gershwin that I've seen before include "Ira -; US lyricist" , "George ........ composed ` `Porgy and Bess' '" , "Scorer" , "American composer" , "George and Ira ..., American musical brothers" .)