As Di having left, lively party’s ending (8)

I believe the answer is:

quashing

'ending' is the definition.

'as di having left lively party's' is the wordplay.
'as' becomes 'qua' (I've seen this before).
'having left' indicates named letters should be taken away.
'lively party' becomes 'shindig' (I've seen this before).
'shindig' with 'di' taken away is 'shing'.
'qua'+'shing'='QUASHING'

I've seen this clue in The Times.

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