An actress who doesn't get the ingenue (aka romantic pretty-girl main-character) roles, but ends up playing the wierd or kooky character every time. Also just girls in real life who never get to be considered the sweet popular one, but who are actually more fun because they're hilarious.
"We're not going to let you audition for the part of Juliet. You're really more of a Nongenue. We're going to cast you as her fat nurse."