We have plenty of colourful ways of describing people and their personalities in English. Some of these expressions are positive, while others are used to criticise someone’s behaviour. Today let's take at six informal idioms for describing very different kinds of people. 1. If someone is a wet blanket, they are a person who spoils other people’s enjoyment by being boring, complaining, or refusing to join in with an activity. This expression is usually disapproving: "Don’t be such a wet blanket! Come and dance with us!" 2. Someone who is a loose cannon is likely to behave in an unpredictable way and may cause problems because they act or speak without thinking about the consequences. We often use this expression when someone’s behaviour could have a negative effect on other people: "You never know what Sarah is going to say in a meeting. She can be a bit of a loose cannon." 3. If you describe someone as a rotten apple, you mean that they are a bad or dishonest person who has a negative influence on the people around them. The expression comes from the idea that one rotten apple can cause others in the same container to rot too: "Don’t let one rotten apple ruin the atmosphere in the whole group." 4. In contrast, a tough cookie is someone who is strong and determined and who is not easily upset, frightened, or defeated. We often use this expression approvingly: "She’s a tough cookie – I’m sure she’ll get through this." 5. Finally, a couch potato is someone who spends a lot of time sitting or lying down, usually watching television or doing very little physical activity. This expression is usually humorous rather than seriously critical: "I spent the whole weekend being a couch potato and watching old films." Which of these expressions would you be most likely to use to describe someone you know? And do you know any other colourful English idioms for describing people?