Plural form of headlong when used as a noun, or archaic third-person singular verb form meaning 'plunges or falls head-first'.
From Middle English 'hedlonge,' originally an adjective/adverb meaning head-first. In Middle English, verbs could be formed directly from adverbs describing manner of movement.
This word shows how English morphology has shifted—we used to be able to use adverbs as verbs more freely, but modern English standardized this less, making 'headlongs' sound distinctly archaic.
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