Alt-right. I never heard this term in my life until recently. It comes across to me as just another effort to label a bunch of people, force them all into a single group, and insult them.
The media and Clinton made it a pejorative. The alt-right exists as an ideological group, much like conservatives, with a list of attributes which describes alt-right. I agree with some of those as they are common with some conservatarian attributes. However, I don't agree with the more right-wing collectivist parts of the platform, like nationalism.