Deals with internal information leading to severe lectures (6)
I believe the answer is:
trades
'deals' is the definition.
('trade' can be a synonym of 'deal')
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for trades that I've seen before include "Buys and sells shares" , "Barters" , "blows" , "Stared (anag)" , "Occupations" .)