New monastic plan gets people grumbling (12)

I believe the answer is:

complainants

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'gets people grumbling' is the definition.
I can't tell whether this definition defines the answer.

'new monastic plan' is the wordplay.
'new' indicates anagramming the letters.
'monastic'+'plan'='monasticplan'
'monasticplan' is an anagram of 'COMPLAINANTS'.

Can you help me to learn more?

I've seen this clue in The Guardian.

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