Silently acting an operatic part is no good (6)

I believe the answer is:

miming

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'silently acting' is the definition.
'miming' can be an answer for 'acting' (thesaurus). I'm not certain of the 'silently' bit.

'operatic part is no good' is the wordplay.
'operatic part' becomes 'mimi' (I can't justify this - if you can you should give a lot more credence to this answer).
'is no good' becomes 'ng' (abbreviation).
'mimi'+'ng'='MIMING'

'an' is the link.

Can you help me to learn more?

(Other definitions for miming that I've seen before include "Pretending to sing" , "Acting without words" .)

I've seen this clue in the Evening Standard.

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