Rent during course is a risky game (8)
I believe the answer is:
roulette
'risky game' is the definition.
'roulette' can be an answer for 'game' (roulette is a kind of game). I am not sure about the 'risky' bit.
'rent during course' is the wordplay.
'rent' becomes 'let' (I've seen this in another clue).
'during' means one lot of letters goes inside another.
'course' becomes 'route' (both can mean a path).
'let' inserted inside 'route' is 'ROULETTE'.
'is a' acts as a link.
Can you help me to learn more?
(Other definitions for roulette that I've seen before include "Game of chance with small ball" , "Casino game" , "Gambling game with small ball and revolving disc (8)" , "sort of gambling" , "French gambling" .)