In a drooping manner; with a sad, tired, or weak appearance or movement.
From 'droopy' plus the adverb-forming suffix '-ly', which transforms adjectives into adverbs describing how an action is performed. The '-ly' suffix comes from Old English '-lice'.
The '-ly' adverb suffix is so common we barely notice it, but it's one of English's most useful word-building tools—most adverbs are made by simply sticking '-ly' on an adjective!
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