Title: 10 Common English Idioms and Their Meanings Break a leg: This is a phrase used to wish someone good luck, especially before a performance or event. Barking up the wrong tree: This means to pursue the wrong course of action or to have a mistaken belief about something. Piece of cake: This is used to describe something that is very easy or simple to do. A blessing in disguise: This means that something that seems bad or unfortunate at first can actually have a good outcome. It's raining cats and dogs: This is a phrase used to describe heavy rainfall. Hit the nail on the head: This means to do or say something exactly right. Cost an arm and a leg: This means something is very expensive. Bite the bullet: This means to endure a difficult or unpleasant situation. Keep your chin up: This is a phrase used to encourage someone to stay positive or optimistic. A penny for your thoughts: This is a way of asking someone what they are thinking about.