Current teacher's retiring, one controlling a pupil? (4)
I believe the answer is:
iris
'pupil?' is the definition.
(thesaurus)
'current teacher's retiring' is the wordplay.
'current' becomes 'I' (symbol for electric current).
'teacher' becomes 'sir' (way of addressing a male teacher).
'retiring' shows that the letters should be reversed in order.
'sir' backwards is 'ris'.
'i'+'ris'='IRIS'
'one controlling a' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for iris that I've seen before include "bit of mince pie" , "Female" , "plant with showy flowers" , "Ms Murdoch" , "Pupil is at the centre of this" .)