Get wind of doctor breaking law (6)
I believe the answer is:
rumble
'get wind of' is the definition.
(UK term for meaning to discover something)
'doctor breaking law' is the wordplay.
'doctor' becomes 'mb' (Bachelor of Medicine, Medicinae Baccalaureus).
'breaking' indicates putting letters inside.
'law' becomes 'rule' (rule is a kind of law).
'mb' going inside 'rule' is 'RUMBLE'.
(Other definitions for rumble that I've seen before include "Fight between rival gangs of adolescents" , "Discover the truth about" , "uncover secrecy perhaps" , "Find out the truth" , "Make a low noise" .)