You might hear that same teacher warn a student not to “monkey around” with a valuable piece of equipment. You “monkey around” with something when you do not know what you are doing. You are touching or playing with something you should leave alone.

Also, you can “monkey around” when you feel like doing something, but have no firm idea of what to do. For example, you tell your friend you are going to spend the day “monkeying around” with your car. Well, you do not have any job or goal in mind -- it is just a way to pass the time.

​“Monkey business” usually means secret -- maybe illegal -- activities. A news report may say there is “monkey business” involved in building the new airport, with some officials getting secret payments from builders.

You may “make a monkey out of” someone when you make that person look foolish. Some people “make a monkey out of” themselves by acting foolish or silly.

​If one monkey has fun, imagine how much fun “a barrel of monkeys” can have! If your friend says he had “more fun than a barrel of monkeys” at your party, you know that he had a really good time.

“Monkey suits” are common names for clothes or uniforms soldiers wear.

In earlier years in many American cities, you would find men playing musical hand organs on the street. Dancing to the music would be the man’s small monkey dressed in a tight-fitting, colorful jacket similar to a military uniform. So, people began to call a military uniform a “monkey suit.”