To spite is to intentionally annoy, hurt, or upset without self-benefit. Spiteful words or actions are delivered in such a way that it is clear that the person is delivering them just to annoy, hurt, or upset. When the intent to annoy, hurt, or upset is shown subtly, behavior is considered catty.
In his 1929 examination of emotional disturbances, Psychology and Morals: An Analysis of Character, J. A. Hadfield uses deliberately spiteful acts to illustrate the difference between disposition and sentiment.