Sort out a profit -- one grand, possibly (10)
I believe the answer is:
pianoforte
'grand possibly' is the definition.
(grand is a kind of pianoforte)
'sort out a profit one' is the wordplay.
'sort out' indicates anagramming the letters.
'a'+'profit'+'one'='aprofitone'
'aprofitone' is an anagram of 'PIANOFORTE'.
(Other definitions for pianoforte that I've seen before include "Joanna" , "Keyboard instrument" , "might be grand" .)