Teacher heads off spluttering, in rage (3)
I believe the answer is:
sir
'teacher' is the definition.
(way of addressing a male teacher)
'heads off spluttering in rage' is the wordplay.
'heads off' suggests taking the first letters (the 'heads' of the words).
The first letters of 'spluttering in rage' is 'SIR'.
(Other definitions for sir that I've seen before include "Poet and novelist" , "Knight's title" , "Formal and deferential address to a man" , "Polite form of address to a man" , "Title of Kt or Bart" .)