Decent sort of piano (7)
I believe the answer is:
upright
I believe this is a double definition.
'decent' is the first definition.
(thesaurus)
'sort of piano' is the second definition.
(I know that upright is a type of piano)
(Other definitions for upright that I've seen before include "Standing vertically - post" , "Vertical, erect" , "Keyboard instrument" , "In a vertical position" , "Vertical like rugby goal post" .)