There are dozens of idioms in English that start with "keep," and there are a few that combine "keep" with some body part.
There are even a few that use "keep" and types of clothing! (We'll save that for another post, as well as more "keep" and body part idioms . .)
Try using these idioms today when you're talking with your friends or colleagues:
1.) Keep an Eye Out
This means to watch closely for something to happen. For example, you might say to a work colleague, "Keep an eye out for the latest shipment. Let me know when it arrives."
2.) Keep (Someone) at Arm's Length
This means that you should not get too close to someone. Stay a safe distance away. For example, you might say of a new boyfriend or girlfriend that you want to keep him/her at arm's length until you get to know him/her better.
3.) Keep (Someone) on (My, Your, His, Her, Our, Their) Toes
This means that you focus your attention on someone to ensure he/she is doing his/her job. For example, you might say, "My boss is always watching me, trying to keep me on my toes."
Watch out for more idioms with "keep" in another post!