prisluškivač

1. eavesdropper; wiretapper
   Prisluškivač je snimao sve njihove telefonske razgovore. — The wiretapper recorded all their phone calls.
   Zatvori vrata, ne treba nam nijedan prisluškivač. — Close the door, we don't need any eavesdroppers.
2. (device) bug; listening device
   U telefonu su našli prisluškivač. — They found a bug in the phone.
   U kancelariji su pronađeni prisluškivači. — Listening devices were found in the office.

The word denotes both the person and the device; the device is also called "prislušni uređaj" or colloquially "bubica".