Stop doctor boarding E-boat (7)
I believe the answer is:
embargo
'stop' is the definition.
(I know that embargo is a type of stop)
'doctor boarding e-boat' is the wordplay.
'doctor' becomes 'MB' (Bachelor of Medicine, Medicinae Baccalaureus).
'boarding' is an insertion indicator.
'boat' becomes 'argo' (I've seen this before).
'e'+'argo'='eargo'
'mb' put into 'eargo' is 'EMBARGO'.
(Other definitions for embargo that I've seen before include "Trade sanction" , "Ban or restraint on trade" , "Trade stoppage" , "Commercial break" , "Government order imposing a trade barrier" .)