Ferry operator retaining games supervisor (8)
I believe the answer is:
chaperon
'supervisor' is the definition.
(I've seen this before)
'ferry operator retaining games' is the wordplay.
'ferry operator' becomes 'charon' (I can't justify this - if you can you should give a lot more credence to this answer).
'retaining' indicates putting letters inside (inserted letters are held or retained).
'games' becomes 'PE' (abbreviation for Physical Education).
'charon' placed around 'pe' is 'CHAPERON'.
Can you help me to learn more?
(Other definitions for chaperon that I've seen before include "One accompanies the vulnerable" , "One who accompanies and supervises" , "One accompanies to supervise" , "One accompanies and looks after another person or group" , "Escort" .)