Widow bet on event? On the contrary (7)
I believe the answer is:
dowager
'widow' is the definition.
(term for an aristocratic widow)
'bet on event? on the contrary' is the wordplay.
I cannot really understand how this works, but
'bet' could be 'wager' (synonyms) and 'wager' is present in the answer.
'event?' could be 'do' (do is a kind of event) and 'do' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for dowager that I've seen before include "Important widow" , "Widow with title or property from her husband" , "One of 16 [OLD GIRLS]" , "Wordage for the widow of a peer" , "Widow with inheritance" .)