Elderly noblewoman’s bet daughter unveiled at first during party game (7,7)
I believe the answer is:
dowager duchess
'bet daughter unveiled at first during party game' is the definition.
I can't judge whether this definition defines the answer.
'elderly noblewoman's' is the wordplay.
'elderly' becomes 'dowager' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'noblewoman's' becomes 'duchess'' (duchess is a kind of noblewoman).
'dowager'+'duchess'='DOWAGER DUCHESS'
Can you help me to learn more?
(Another definition for dowager duchess that I've seen is " Nobleman's widow".)