Touch instrument on the counter (4)
I believe the answer is:
abut
'touch' is the definition.
(abutting is a kind of touching)
'instrument on the counter' is the wordplay.
'instrument' becomes 'tuba' (tuba is a kind of instrument).
'on the counter' says the letters should be written backwards (counter can mean in the opposite direction).
'tuba' in reverse letter order is 'ABUT'.
(Other definitions for abut that I've seen before include "Be next to -- share a boundary" , "Lie next to" , "Tuba (anag)" , "Join" , "End or lean against, say a building" .)