An archaic word meaning to bite away at something or to gnaw continuously until destroyed.
From Old English 'for-' (completely, away) + 'bitan' (to bite). The 'for-' prefix intensifies or completes the action, so 'forbite' means to bite through or consume entirely by biting.
Old English prefixes like 'for-' were super productive—they could attach to almost any verb to change its meaning fundamentally, which is why you find all these 'for-' words that seem weird to modern ears.
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