Has it a sort of hollow charm? (6)

I believe the answer is:

grotto

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'hollow charm?' is the definition.
'grotto' can be an answer for 'hollow'. I am not certain of the 'charm?' bit.

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for grotto that I've seen before include "In company (with); over length of" , "(Imitation) cave" , "A picturesque cave as in Lourdes (6)" , "Type of cave, often with religious significance" , "Small cave as at Lourdes" .)

I've seen this clue in the Evening Standard.

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