The term for any female slut that attends any highschool and has to use any of the following for attention:
1. Being pregnant two times a week.
2. Having "Lots" of sex.
3. Has every STD known to man.
4. Gets 'raped' in the band room.
5. Be approximately 14-16 and claim that you are 18 years old and go on blogging websites and post pictures of adult actress' because your contenance is so wretched a paperbag wouldn't even be able to do you justice.
A Gillis is also a longhand notation for a very and highly contagious sexually transmitted disease, Hepatitis G(Gillis).
Hep. G has three stages...
1. You are extremely horny and hideous as FUCK.
2. Your crotch turns into a contagion for deadly diseases and plagues.
3. You die.
Gillis is a plague that has ravaged Crivitz. Although there is no known cure for her, cans of Lysol have died valiantly trying to end the sufferings of her tyranical reign. She must be burnt and forgotten!
"Gillis, close your legs you filthy fucking whore!"
"Gillis, you're so easy a caveman can do you."
"Ya know, you're as loose as a glass of water"