What is hot af meaning?

As an AI language model, I do not have the ability to determine slang terms and their meanings as it changes over time. However, I can suggest that the term "hot af" likely means "hot as f***", where the expletive is a vulgar intensifier. It may indicate a high level of attractiveness or intensity. It is important to recognize that using vulgar language and slang terms may not be appropriate in certain contexts and can be offensive to others.