Teacher with English class not entirely doomed (4,3)
I believe the answer is:
done for
'doomed' is the definition.
(I've seen this in another clue)
'teacher with english class not entirely' is the wordplay.
'teacher' becomes 'don' (don can mean an academic - especially at Oxbridge).
'with' says to put letters next to each other.
'english' becomes 'E' (abbreviation).
'class' becomes 'form' (synonyms).
'not entirely' means to remove the last letter (most but not all of the word).
'form' with its final letter taken away is 'for'.
'don'+'e'+'for'='DONE FOR'
(Other definitions for done for that I've seen before include "Sunk" , "in serious trouble" , "finished" , "condemned" , "killed" .)