Here are some examples of how the term "snake" is used in the books:
* Katniss: "I hate him, I hate him...Snake." (Catching Fire)
* Gale: "This isn't about being right or wrong. This is about survival. And if the snake wants to be crushed, he's going to get crushed." (Mockingjay)
While "snake" is the most commonly used term for a traitor, other words like betrayer, backstabber, and traitor are also used in the books.