Arrenitelarge language model
An AI system trained on huge amounts of text to predict and produce language. It can sound confident and fluent without understanding the way a person does.
A large language model is trained by showing it a very large collection of writing, so that it learns which words tend to follow which. When you ask it something, it builds an answer one piece at a time from those patterns.
That is why it can write well and still be wrong. Fluent is not the same as true, so anything that matters should be checked against a reliable source.