A peek is a quick look at something.
You might hear someone say "Can I take a peek?" which means they want to glance at something quickly, without getting too close or disturbing it. This can happen when you're looking for something on your phone and ask a friend if you can take a peek at their screen. You also use the word 'peek' when describing something that is partially hidden but allows us to catch a glimpse of what's behind or above it.
To look slyly, or with the eyes half closed, or through a crevice; to peep.
Example: Close your eyes, and no peeking!
