Biggest purple people eater scoffed triplets for starters (8)

I believe the answer is:

plumpest

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'biggest' is the definition.
Both the definition and answer are superlative adjectives. Maybe they are linked in a way I don't understand?

'purple people eater scoffed triplets for starters' is the wordplay.
'purple' becomes 'plum' (I have seen 'Dark purple' mean 'plum' so perhaps 'purple' could also mean 'plum').
'for starters' suggests taking the first letters.
The first letters of 'people eater scoffed triplets' is 'pest'.
'plum'+'pest'='PLUMPEST'

Can you help me to learn more?

(Another definition for plumpest that I've seen is " better fed than the rest?".)

I've seen this clue in The Independent.

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