Beat a medical man in the finish (7)
I believe the answer is:
lambast
'beat' is the definition.
(I know that lambast is a type of beat)
'a medical man in the finish' is the wordplay.
'medical man' becomes 'MB' (someone with a Bachelor of Medicine degree).
'in' indicates putting letters inside.
'the finish' becomes 'last' ('last' can be a synonym of 'finish').
'a'+'mb'='amb'
'amb' put into 'last' is 'LAMBAST'.
(Other definitions for lambast that I've seen before include "Thrash" , "Criticise severely" , "rubbish" , "Be harsh critic of" , "Harshly criticise" .)