Teacher was successful, we hear, and excelled (9)
I believe the answer is:
surpassed
'excelled' is the definition.
('surpass' can be a synonym of 'excel')
'teacher was successful' is the wordplay.
'teacher' becomes 'sur' (I can't explain this - if you can you should give a lot more credence to this answer).
'was successful' becomes 'passed' (I've seen this before).
'sur'+'passed'='SURPASSED'
'we hear and' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for surpassed that I've seen before include "capped" , "outclassed" , "beaten" , "Outdid" .)