Teacher takes exception to the geniuses (11)
I believe the answer is:
masterminds
'the geniuses' is the definition.
('mastermind' can be a synonym of 'genius')
'teacher takes exception' is the wordplay.
'teacher' becomes 'master' (I've seen this before).
'takes exception' becomes 'minds' (I am not sure about this - if you are sure you should believe this answer much more).
'master'+'minds'='MASTERMINDS'
'to' is the link.
Can you help me to learn more?
(Another definition for masterminds that I've seen is " planners".)