Doctor seeing work decrease (4)
I believe the answer is:
drop
'decrease' is the definition.
(I know that drop is a more specific form of decline)
'doctor seeing work' is the wordplay.
'doctor' becomes 'dr' (abbreviation).
'seeing work' becomes 'op' (abbreviation for opus).
'dr'+'op'='DROP'
(Other definitions for drop that I've seen before include "small amount of alcohol" , "Fall; abandon" , "Plunge" , "Tiny bit of liquid" , "shed" .)