A more thorough explanation:

Protestatio contraria facto is a Latin term used in law. It refers to a situation where someone protests against something, but their actions contradict their protest.

For example, if a person protests against animal cruelty but then goes and buys products that are tested on animals, they are engaging in protestatio contraria facto. Another example is if a politician protests against corruption but then is caught accepting bribes, they are also engaging in protestatio contraria facto.

These examples illustrate the definition because in both cases, the person is saying one thing but doing the opposite. They are protesting against something, but their actions show that they don't really believe in what they are saying.