Training doctor badly (5)
I believe the answer is:
drill
'training' is the definition.
(I've seen this before)
'doctor badly' is the wordplay.
'doctor' becomes 'dr' ('Dr' can be a synonym of 'doctor').
'badly' becomes 'ill' ('ill' can be adverbial as in 'ill-advised').
'dr'+'ill'='DRILL'
(Other definitions for drill that I've seen before include "Bore (a hole); fabric" , "Routine" , "Monkey" , "Square-bashing" , "Tool, instruction" .)