Allowing something to happen without outside influence. For Example: The full saying is usually “let nature take its course” which means “just relax and let’s just see how everything works out in the end.”

Someone who watches a lot of television and is therefore assumed to be lazy. For Example: “Did you invite Greg to the party?” “Yes, I did, but I doubt he’ll come. That guy is such a couch potato.”

In a difficult situation. For Example: “When Mary told me I had to choose between her or my career, I really found myself in a tight corner.”

To become tempermental or nervous. For Example: “When the store clerk told Bill they were out of beer, he lost his cool and shouted that he would never return to the store again.”

To remain calm in an adverse situation. For Example: When someone keeps their cool, they don’t become emotionally upset or distracted in a scenario where most people might.