Just a piano? (7)
I believe the answer is:
upright
I believe this clue is a double definition.
'just' is the first definition.
(both can mean fair or honest)
'a piano' is the second definition.
(I know that upright is a type of piano)
(Other definitions for upright that I've seen before include "Pig hurt (anag) -- noble" , "Pole; principled" , "Key item" , "Joanna" , "Type of piano" .)