peek · verb I /piːk/
peek out/at/through, etc.
C2 to look at something for a short time, often when you do not want other people to see you
Dictionary examples:
She covered her face with her hands and peeked at them through her fingers.
Close your eyes and don't peek!
Learner example:
Just to make sure I raised myself on an elbow and peeked out my window; my thought showed to be right. (Certificate of Proficiency in English; C2; Swedish)
peek · noun C /piːk/
peek
C1 a quick look
Dictionary example:
She took a peek down the hall.
Learner example:
One can find an example by just taking a peek at a history of any royal dynasty, or even a wealthy merchant family. (International English Language Testing System; C1; Russian)