Eavesdropper

(n.) One who stands under the eaves, or near the window or door of a house, to listen; hence, a secret listener.

Thesaurus Entries

Paul Pry, Peeping Tom, audient, auditor, busybody, gossip, hearer, hearkener, inquirer, inquisitive, inquisitor, listener, nosy Parker, overhearer, pry, querier, querist, questioner, quidnunc, rubberneck, rubbernecker, scopophiliac, sightseer, snoop, snooper, voyeur, yenta