Fell, dropped, or collapsed heavily and messily, or (of a project or performance) failed completely and disappointingly.
From Middle English and Old English, likely derived from imitative origins related to 'flap.' The word gained its 'failure' meaning in the 20th century, especially in entertainment and business contexts.
The double meaning of 'flopped' is perfect—something physically heavy and awkward falling mirrors the social awkwardness of a complete failure, which is why the word captures both the sound and the feeling of disaster.
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