Old stringed instrument from hilly region (4)
I believe the answer is:
lyre
'old stringed instrument' is the definition.
(I've seen this before)
'from hilly region' is the wordplay.
'from' indicates a hidden word.
'LYRE' can be found hidden inside 'hilly region'.
(Other definitions for lyre that I've seen before include "Old musical instrument with strings in U-shaped frame" , "Harp used by ancient Greeks" , "Old instrument, like a harp" , "Ancient musical instrument - sounds mendacious" , "Ancient Greek harp" .)