Present participle of 'folly' as a verb; engaging in foolish or silly behavior; acting without proper thought.
From the verb 'folly' (to act foolishly) plus the gerund/participle suffix '-ing'. 'Folly' as a verb derives from the noun 'folly'.
Using 'folly' as a verb is delightfully rare—it's like the word 'adulting' today; people created it because existing words didn't capture exactly how they were describing foolish behavior.
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