Someone who does not use any animal products (which is near impossible). It has been proven that to be a vegan one must have a ridiculous superiority complex. This is often mistaken by the vegan and other vegans as enlightenment. This massive ego stimulation often results in insulting "meat-eaters" undeservedly, and the delusion that they are actually making a change. This also involves constant bragging about how much they love the lifestyle.
1. "If you are not a vegan, you are a terrible, terrible person incapable of feeling compassion or love because you can stomach the thought of killing a cow. Hold on, I have to finish my tofu and soy milk."
2. "As a vegan, I would sooner kill one human infant than two cows."
(Note: Number 2 is a direct quote from a vegan I know.)