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.

An underdog whose determination usually results in success. For Example: “No one thought Mark stood a chance in that fight, but he is one tough cookie and proved everyone wrong.”

A phrase that indicates the phrase you’re using to describe something is being used with sarcasm. For Example: You might say, “Bill thinks one day he’s going to ‘save the company’ in inverted commas.” What you’re implying is that you don’t believe Bill genuinely intends to save the company.

With great success. For Example: If Sarah needed to score 80% to pass a test and she scored 97% on the test, you would say “she passed the test with flying colors.”