Error from teacher upset special pupil (7)
I believe the answer is:
misstep
'error' is the definition.
(misstep can mean an error or mistake)
'teacher upset special pupil' is the wordplay.
'teacher' becomes 'miss' (a female teacher might be addressed 'miss').
'upset' says the letters should be written in reverse.
'special pupil' becomes 'pet' (I have seen 'Favourite pupil ' mean 'pet' so perhaps 'pupil' could also mean 'pet'. I am not sure about the 'special' bit.).
'pet' in reverse letter order is 'tep'.
'miss'+'tep'='MISSTEP'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for misstep that I've seen before include "False move" , "bad move" , "Badly judged footing" , "Error" , "Badly judged move" .)