Conservative drive for discipline (7)
I believe the answer is:
chasten
'for discipline' is the definition.
(I've seen this before)
'conservative drive' is the wordplay.
I cannot quite see how this works, but
'conservative' could be 'c' (UK political abbreviation) and 'c' is present in the answer.
The remaining letters 'hasten' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for chasten that I've seen before include "Have a restraining effect on (someone)" , "Subdue pride of with a stench" , "Subdue, correct by punishing" , "Castigate or punish" , "Moderate" .)