Fruit fly perhaps is largest in size (8)

I believe the answer is:

plumpest

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'perhaps is largest in size' is the definition.
I can't judge whether this defines the answer.

'fruit fly' is the wordplay.
'fruit' becomes 'plum' (plum is a kind of fruit).
'fly' becomes 'pest' (I am not sure about this - if you are sure you should believe this answer much more).
'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 Hindu.

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