MISTAKE (5 letters) The term MESSAGE ERROR can be broken down into two words: OOPS (4 letters) and MISTAKE (5 letters). OOPS is an informal expression used to indicate surprise, embarrassment, or dismay, while MISTAKE is an action or judgment that is misguided or wrong. Together, these two words form the phrase MESSAGE ERROR, which is a technical term used to describe an error in a message sent over a computer network.