keep one's eyes open

Idioms and Phrases

Also, keep one's eyes peeled or skinned . Be watchful and observant. For example, We should keep our eyes open for a change in the wind's direction , or Keep your eyes peeled for the teacher . The first phrase dates from the late 1800s; the second and third, both colloquial and alluding to the lids not covering the eyes, date from the mid-1800s and 1830s, respectively.