An Unfriendly artificial intelligence (or UFAI) is an artificial general intelligence capable of causing great harm to humanity, and having goals that make it useful for the AI to do so. The AI’s goals don’t need to be antagonistic to humanity’s goals for it to be Unfriendly; there are strong reasons to expect that almost any powerful AGI not explicitly programmed to be benevolent to humans is lethal. A paperclip maximizer is often imagined as an illustrative example of an unFriendly AI indifferent to humanity. An AGI specifically designed to have a positive effect on humanity is called a Friendly AI.
Eliezer S. Yudkowsky (2008). “Artificial Intelligence as a Positive and Negative Factor in Global Risk”. Global Catastrophic Risks. Oxford University Press. (PDF)