Devil is a noun that primarily refers to the supreme spirit of evil in Christianity and other religions.
Other meanings include:
1. An evil spirit or demon
2. A very wicked or cruel person
3. Used to express annoyance or surprise ("What the devil?")
4. A person with specified characteristics ("poor devil")
5. In cooking, to prepare food with hot seasoning ("deviled eggs")
Common phrases: "Speak of the devil", "Better the devil you know", "Devil's advocate"