Make a bet about regulation regarding discharge (8)
I believe the answer is:
purulent
'regulation regarding discharge' is the definition.
I can't judge whether this defines the answer.
'make a bet about' is the wordplay.
'make' becomes 'rule' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a bet' becomes 'punt' (I've seen this before).
'about' means one lot of letters goes inside another.
'rule' inserted inside 'punt' is 'PURULENT'.
Can you help me to learn more?
(Another definition for purulent that I've seen is " pussy?".)