Sheep's clothing is a phrase used to describe a person or group who presents themselves as something they are not. It is derived from the fable of 'The Wolf in Sheep's Clothing' which tells the story of a wolf who disguises himself as a sheep in order to gain access to the flock. The term has since been used to describe people who pretend to be something they are not in order to deceive others. WOOL is the most common material used to make sheep's clothing, as it is a natural fiber that is both durable and warm.