Time repeatedly invested in game — it's a gamble (5)
I believe the answer is:
lotto
'a gamble' is the definition.
(I've seen this before)
'time repeatedly invested in game' is the wordplay.
'time' becomes 't' (abbreviation).
'repeatedly' shows that letters should be duplicated.
'invested in' indicates putting letters inside.
'game' becomes 'loo' (historic card game found in Jane Austen novels).
't' doubled is 'tt'.
'tt' going inside 'loo' is 'LOTTO'.
'it's' is the link.
(Other definitions for lotto that I've seen before include "house" , "Game of chance similar to bingo" , "gamble" , "Children's game, housey-housey" , "Children's game similar to bingo" .)