demon, evil spirit, unclean spirit

Definition:

All these terms refer to demons, which are spirit beings that oppose God's will.

God created angels to serve him. When the devil rebelled against God, some of the angels also rebelled and were thrown out of heaven. It is believed that demons and evil spirits are these "fallen angels."
Sometimes these demons are called "unclean spirits." The term "unclean" means "impure" or "evil" or "unholy."
Because demons serve the devil, they do evil things. Sometimes they live inside people and control them.
Demons are more powerful than human beings, but not as powerful as God.

The term "demon" could also be translated as "evil spirit."
The term "unclean spirit" could also be translated as "impure spirit" or "corrupt spirit" or "evil spirit."
Make sure that the word or phrase used to translate this term is different from the term used to refer to the devil.
Also consider how the term "demon" is translated in a local or national language. (See: How to Translate Unknowns)

26:09 Many people who had demons in them were brought to Jesus. When Jesus commanded them, the demons came out of the people, and often shouted, "You are the Son of God!"
32:08 The demons came out of the man and entered the pigs.
47:05 Finally one day when the slave girl started yelling, Paul turned to her and said to the demon that was in her, "In the name of Jesus, come out of her." Right away the demon left her.
49:02 He (Jesus) walked on water, calmed storms, healed many sick people, drove out demons, raised the dead to life, and turned five loaves of bread and two small fish into enough food for over 5,000 people.