Erred in becoming more eggheaded (7)

I believe the answer is:

nerdier

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'more eggheaded' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'erred in becoming' is the wordplay.
'becoming' indicates anagramming the letters.
'erred'+'in'='erredin'
'erredin' with letters rearranged gives 'NERDIER'.

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I've seen this clue in the Sydney Morning Herald.

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