In a drooping manner; with a drooping quality or characteristic movement.
From the present participle 'drooping' plus the adverb suffix '-ly'. This is a more formal or emphatic way of creating an adverb from the verb form itself rather than the adjective.
English gives us multiple ways to make adverbs—'droopily' from the adjective and 'droopingly' from the participle—which is why English can feel redundant but also beautifully flexible!
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