in a manner that is suitable, appropriate, or flattering in appearance.
From 'becoming' (adjective) plus the '-ly' adverb suffix. The word 'becoming' itself comes from 'become', shifting from 'arriving at' to 'suitable for', with the adverb form showing graceful conduct.
The '-ly' suffix is English's favorite way to turn adjectives into adverbs, but 'becomingly' is special—it's a sophisticated word meaning 'in a way that shows good taste and propriety,' mostly used in older formal writing.
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