Crooked master was first to give class detention (9)
I believe the answer is:
malformed
'crooked' is the definition.
Both the definition and answer are adjectives. Perhaps there's a link between them I don't understand?
'master was first to give class detention' is the wordplay.
I cannot quite see how this works, but
'master' could be 'ma' (Master of Arts) and 'ma' is located in the answer.
'to' could be 'for' and 'for' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for malformed that I've seen before include "in bad shape" , "faulty!" , "disfigured" , "Badly-shaped" , "Misshapen" .)