1. slang To engage in intellectual, typically introverted activities. I spent most of my time as a kid nerding out in my room learning about different kinds of insects.
2. slang To engage in activities or discussions related to or revolving around video games, high fantasy, science fiction, comic books, etc. I have a group of friends whom I nerd out with on the weekends, usually by playing video games or watching Star Trek.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.