Derogatory adjective used to disparage enviromentally conscious people. An envirotard may simply like eating organic food, or they may be really active in the enviromental movement. People who, for some reason, find taking care of the earth offensive or somehow stupid, call people who care envirotards.
Man, I wanted to bone that chick but she is a vegan envirotard who won't fuck smokers or men that eat meat. What a commie bitchwad!