German composer either pianissimo ___ ? (4)
I believe the answer is:
orff
'german composer' is the definition.
(Carl Orff, 1895-1982)
'either pianissimo ?' is the wordplay.
'either' becomes 'or' (I've seen this in another clue).
'pianissimo ?' becomes 'ff' (I can't explain this - if you can you should give a lot more credence to this answer).
'or'+'ff'='ORFF'
(Other definitions for orff that I've seen before include "With all instruments" , "Composer of Carmina Burana, d. 1982" , "German composer, Carl d. 1982" , "Carl -, wrote Carmina Burana" , "German who scored" .)