Retiring English teacher getting pay increase (4)
I believe the answer is:
rise
'pay increase' is the definition.
(I've seen this in other clues)
'retiring english teacher getting' is the wordplay.
'retiring' shows that the letters should be reversed in order.
'english' becomes 'E' (abbreviation).
'teacher' becomes 'sir' (a male teacher might be addressed as 'sir').
'getting' says to put letters next to each other.
'e'+'sir'='esir'
'esir' back-to-front is 'RISE'.
(Other definitions for rise that I've seen before include "Get or stand up" , "Growth" , "Provide (an opportunity)" , "Hill" , "Ascend" .)