Employ specialist to remove piano (5)
I believe the answer is:
exert
'employ' is the definition.
(eg exerting strength is using or employing it)
'specialist to remove piano' is the wordplay.
'specialist' becomes 'expert' (a specialist is an expert in a field).
'to remove' indicates named letters should be taken away.
'piano' becomes 'p' (musical abbreviation).
'expert' with 'p' removed is 'EXERT'.
(Other definitions for exert that I've seen before include "Strain" , "Bring into operation" , "Expend" , "Apply (force)" , "Cause (oneself) to make a strenuous effort" .)