Roomy bag (4)
I believe the answer is:
tote
'roomy bag' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tote that I've seen before include "It takes bets for horse races" , "Form of betting: carry" , "You can bet on this" , "Horse race betting system" , "system for betters" .)