In shop Ian obtained instrument (5)
I believe the answer is:
piano
'instrument' is the definition.
(piano is a kind of instrument)
'in shop ian obtained' is the wordplay.
'in' says the answer is hidden in the clue.
'PIANO' is hidden within 'shop ian obtained'.
(Other definitions for piano that I've seen before include "In music, soflty" , "Quiet (music)" , "Keyboard instrument" , "Franz Liszt's instrument" , "soft passage" .)