Eavesdropping

Cardinals eavesdropping in the Vatican. A painting by Henri Adolphe Laissement, 1895
"Belly-buster" hand-crank audio drill, used during the late 1950s and early 1960s to drill holes into masonry for implanting audio devices

Eavesdropping is the act of secretly or stealthily listening to the private conversation or communications of others without their consent.[1] The practice is widely regarded as unethical, and in many jurisdictions is illegal.

Etymology

The verb eavesdrop is a back-formation from the noun eavesdropper ("a person who eavesdrops"), which was formed from the related noun eavesdrop ("the dripping of water from the eaves of a house; the ground on which such water falls").[2]

An eavesdropper was someone who would hang from the eave of a building so as to hear what is said within. The PBS documentaries Inside the Court of Henry VIII (April 8, 2015)[3] and Secrets of Henry VIII’s Palace (June 30, 2013) include segments that display and discuss "eavedrops", carved wooden figures Henry VIII had built into the eaves (overhanging edges of the beams in the ceiling) of Hampton Court to discourage unwanted gossip or dissension from the King's wishes and rule, to foment paranoia and fear,[3] and demonstrate that everything said there was being overheard; literally, that the walls had ears.[4]