listen in

verb

listened in; listening in; listens in

intransitive verb

1

: to tune in to or monitor a broadcast

2

: to listen to a conversation without participating in it

especially : eavesdrop

listener-in

ˌli-sᵊn-ər-ˈin 

ˌlis-nər-

noun

Synonyms of listen in

• eavesdrop (on)
• hear
• monitor
• spy
• overhear

Examples of listen in in a Sentence

it's not polite to listen in on other people's private conversations

Recent Examples on the Web

New monitors sold in New York must include security features that stop strangers from watching or listening in, and must carry a clear warning label saying the device connects to the internet and that families should use its security settings. — Catherina Gioino, Fortune, 28 Oct. 2026

Crack it, and attackers could pose as your bank or listen in on your messages. — Chris Stokel-Walker, Scientific American, 15 Oct. 2026

If there is a frontline starter available, the club won’t be opposed to listening in hopes to make the club better. — Kansas City Star, 11 Oct. 2026

Fifty-three percent of the audience for AM and FM radio listen in cars, according to the NAB. — Chris Isidore, CNN Money, 11 Oct. 2026

Word History

First Known Use

1905, in the meaning defined at sense 1

Kids Definition

listen in

verb

1

: to listen to a broadcast

2

: eavesdrop