Restrained or cured of going round the Boar's Head (6)
I believe the answer is:
curbed
'restrained' is the definition.
(curbing is a kind of restraining)
'going round the boar's head' is the wordplay.
'going' becomes 'cured' (I can't explain this - if you can you should believe this answer much more).
'round' means one lot of letters goes inside another.
'head' says to take the initial letters.
The initial letter of 'boars' is 'b'.
'cured' placed around 'b' is 'CURBED'.
'or cured of' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for curbed that I've seen before include "Restrained, say horse with strap" , "Placed restrictions on" , "Kept in check" , "Restrained or inhibited" , "Checked or inhibited" .)