You can just search Wikipedia. I assume you have access to the Internet?
It's about the individual's liberty from oppression, equality and usually keeping corporations in check. Ideally. It's about things like the right to healthcare and education, the ability to have an abortion. The right wing of the democratic party is still neoliberals and even some conservatives though, which is why you'll see people say liberals (in the classic sense) aren't liberals (in the modern American sense) and the people arguing against liberals can then be seen as arguing FOR the fascists in that case.
And the shift goes back to the 1930s so not exactly a new definition of liberal either, just newer than the original.