Avoid 'en' shaped like a birthmark (7)

I believe the answer is:

naevoid

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'like a birthmark' is the definition.
I can't judge whether this defines the answer.

'avoid en shaped' is the wordplay.
'shaped' indicates anagramming the letters.
'avoid'+'en'='avoiden'
'avoiden' is an anagram of 'NAEVOID'.

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I've seen this clue in The Guardian.

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