During dramatic interval, dance old mum’s parts (10)

I believe the answer is:

antimasque

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'during dramatic interval dance' is the definition.
I can't judge whether this defines the answer.

'old mum's parts' is the wordplay.
'old' becomes 'antique' (similar in meaning).
'mum's' becomes 'ma's' (ma can mean mother).
'parts' means one lot of letters goes inside another (inserted letters separate or part others).
'antique' going around 'mas' is 'ANTIMASQUE'.

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I've seen this clue in The Times.

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