I must ignore small and mischievous child (3)

I believe the answer is:

elf

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'mischievous child' is the definition.
(I've seen this in another clue)

I cannot understand how the rest of the clue works.

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(Other definitions for elf that I've seen before include "1 ac fairy" , "Robin Goodfellow?" , "Mischievous fairies" , "Diminutive folklore creature" , "Imaginary creature" .)

I've seen this clue in The Sun.

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