noun
eavesdropper
EEVZ-drah-per/ˈiːvzdrɑːpər/
Someone who secretly listens to private conversations.
An eavesdropper hides outside the office door and listens to us.

Etymology
The roof edge and dripping rain originally named the strip of ground where water fell from the eaves. An eavesdropper stood there, beside walls or windows, to overhear private talk inside.
In context
I heard him talking in a low voice of concentrated passion to his wife this gross breach of hospitality had evidently hit upon his tenderest point I'm no eavesdropper so I walked out onto the lawn
More examples
- She lowers her voice to keep eavesdroppers from hearing.
- The eavesdropper pretends to read while listening to their whispered argument.
- We close the window so no eavesdropper can listen in.
Forms
eavesdropper · eavesdroppers
eavesdrop verb — Listen secretly to other people's conversations.
Similar words
- snoop
- Seeks private information by looking around, not just listening.
- spy
- Secretly gathers information through observation or investigation, not necessarily listening.