"Ain't" is a peculiar word, because it stands for the contraction of "am not," "are not," or "is not." In some cases it can also mean "have/has not," but that depends on the local dialect. "Ain't" is primarily used in colloquial context and never in formal speech. Here are some examples comparing colloquial and more formal forms of speech: "I ain't gonna do it." = "I'm not going to do it." "He ain't worth it." = "He's not worth it." "We ain't fools." = "We're not fools. These are just a few examples of how it can be used. The usage can differ depending on the usage. There is even a wikipedia article about it! Here's the link: https://en.wikipedia.org/wiki/Ain%27t I hope this helps! If you have more questions, please let me know.