Chopper to take off without His Majesty? On the contrary (7)
I believe the answer is:
cleaver
'chopper' is the definition.
(a cleaver chops things)
'his majesty? on the contrary' is the wordplay.
'his majesty?' becomes 'CR' (Charles Rex - ie King Charles).
'on' is an insertion indicator (as in clothing 'on' a person).
'the contrary' becomes 'leave' (I can't explain this - if you can you should give a lot more credence to this answer).
'cr' enclosing 'leave' is 'CLEAVER'.
'to take off without' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for cleaver that I've seen before include "(Meat) chopper" , "A butcher's chopping tool" , "Butcher's knife" , "Meat axe" , "Long-bladed hatchet" .)