Composer turned back by force (4)
I believe the answer is:
orff
'composer' is the definition.
(I've seen this before)
'turned back by force' is the wordplay.
'turned' says the letters should be written in reverse.
'back' becomes 'fro' (synonyms).
'by' says to put letters next to each other.
'force' becomes 'F' (symbol used in Physics e.g. f=ma).
'fro' backwards is 'orf'.
'orf'+'f'='ORFF'
(Other definitions for orff that I've seen before include "Carl -, wrote Carmina Burana" , "Rowing boat" , "German who scored" , "Composer of Carmina Burana, d. 1982" , "German composer, Carl d. 1982" .)