Instrument in hermit's place, nothing in addition (5)
I believe the answer is:
cello
'instrument' is the definition.
(cello is a kind of instrument)
'hermit's place nothing in addition' is the wordplay.
'hermit's place' becomes 'cell'.
'nothing in' becomes 'o' (I've seen this in other clues).
'addition' says to put letters next to each other.
'cell'+'o'='CELLO'
'in' acts as a link.
(Other definitions for cello that I've seen before include "large-scale fiddle" , "Viola's bigger brother?" , "Played by Rostropovich" , "Music-maker" , "has strings attached" .)