eavesdrop (v.)youdaoicibaDictYouDict[eavesdrop 词源字典]
"lurk near a place to hear what is said inside," c. 1600, probably a back-formation from eavesdropper. The original notion is listening from under the eaves of a house. Related: Eavesdropping.[eavesdrop etymology, eavesdrop origin, 英语词源]