A person who secretly listens to someone else's private conversation without permission or knowledge.
Middle English 'evesdropper,' combining 'eaves' (roof overhang) with 'dropper' (one who stands in the drip). Originally a literal term for someone standing under a house's eaves.
In old English law, eavesdroppers were actually considered serious criminals — they threatened privacy and security so much that special laws were made to protect the space around buildings where listeners lurked.
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