Free-wheeling game permitted in the busman's round (8)
I believe the answer is:
roulette
'free-wheeling game' is the definition.
'roulette' can be an answer for 'game' (roulette is a kind of game). I am not sure about the 'free-wheeling' bit.
'permitted in the busman's round' is the wordplay.
'permitted' becomes 'let' (to let something happen is to permit it).
'in the' is an insertion indicator.
'busman's round' becomes 'route' (I am not sure about this - if you are sure you should believe this answer much more).
'let' inserted into 'route' is 'ROULETTE'.
Can you help me to learn more?
(Other definitions for roulette that I've seen before include "If Russian, it's a very dangerous game" , "it's for the better, supposedly" , "risky venture" , "SPORT/GAME" , "Half of 1D [GAME OR BIRD]" .)