Work in a shop usually (4)
I believe the answer is:
opus
'work' is the definition.
(an opus is an artistic work)
'in a shop usually' is the wordplay.
'in' says the answer is hidden in the clue.
'OPUS' is hidden in the letters of 'a shop usually'.
(Other definitions for opus that I've seen before include "Work (mus.)" , "Creative work, eg in writing, art or music" , "Musical composition in the soup" , "Artistic work" , "Work of 25 perhaps" .)