To utter short, soft, high-pitched sounds, like those of a baby bird; cheep. To speak in a hesitant, thin, high-pitched voice. A short, soft, high-pitched sound or utterance, like that of a baby bird. A slight sound or utterance: I don't want to hear a peep out of you. Any of various small North American sandpipers. To peek furtively; steal a quick glance. To peer through a small aperture or from behind something. To appear as though emerging from a hiding place: the moon peeping through the clouds. A quick or furtive look or glance. A first glimpse or appearance: the peep of dawn.