Stop doctor boarding E-boat? (7)
I believe the answer is:
embargo
'stop' is the definition.
(I know that embargo is a more specific form of the action stop)
'doctor boarding e-boat?' is the wordplay.
'doctor' becomes 'MB' (Bachelor of Medicine, Medicinae Baccalaureus).
'boarding' indicates putting letters inside.
'boat?' becomes 'argo' (I've seen this before).
'e'+'argo'='eargo'
'mb' placed into 'eargo' is 'EMBARGO'.
(Other definitions for embargo that I've seen before include "Ban on commerce - mob rage (anag)" , "Block" , "Trade sanction" , "Order intended to prevent trade" , "Eg, Rambo? (anag)" .)