listen in

US /ˈlɪs.ən ɪn/
UK /ˈlɪs.ən ɪn/
"listen in" picture
1.

meeluisteren, afluisteren

to listen to a private conversation between other people, without them knowing that you are listening

:
I caught my sister trying to listen in on my phone call.
Ik betrapte mijn zus die probeerde mee te luisteren met mijn telefoongesprek.
The neighbors often listen in on our conversations.
De buren luisteren vaak mee met onze gesprekken.