Rent out during studies -- 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 certain of the 'risky' bit.
'rent out during studies' is the wordplay.
'rent out' becomes 'let' (I've seen this in another clue).
'during' means one lot of letters goes inside another.
'studies' becomes 'route' (I can't justify this - if you can you should believe this answer much more).
'let' put into 'route' is 'ROULETTE'.
Can you help me to learn more?
(Other definitions for roulette that I've seen before include "sort of gambling" , "Whirling numbered wheel" , "gambling business" , "Spinning-wheel game" , "Casino game" .)