Sense: 4 Date: 1900-2000 Origin: people peep2 noun peep2 [countable]1 a quick or secret look at something peep at/into Jon took a peep at his watch.2 a peep informalC a sound that someone makes, or something that they say, especially a complaint: There has not been a peep out of them since bedtime. a peep of protest3x-ref a short high sound, like the sound a mouse or a young bird makes: the peep o