To spite is to intentionally annoy, hurt, or upset even when there might be no (apparent) gain, and even when those actions might cause the person spiting harm, as well. 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.
A "spite victory" is a strategy that does not account for objective victory and focuses solely on personal satisfaction for spiting the opponent. An example is intentionally parking in a parking slot that is reserved for someone with whom you have a personal vendetta; this would lead to your car's being towed but would generate personal satisfaction knowing you had prevented your enemy from using the slot.