Fresh growth starting to thrust on top of fake growth (4)

I believe the answer is:

twig

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But I can't explain it at all! Could you help me understand?

(Other definitions for twig that I've seen before include "Division of branch" , "Informally grasp meaning" , "small piece in plane, say" , "Suddenly comprehend" , "Suddenly catch" .)

I've seen this clue in The Hindu.

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