One step beyond fanboy or fangirl, a fanwhore is someone who is so insanely obsessed with something they treat it practically like a religion and will physically harm others who disagree with it.
Twilight fanwhore: "OMG TWILIHTGT IS LIEK THE BESTEST BOOK EVAR1!11! STEPHANY MIYER IZ A GENIOIS!111"
Sane person: "Twilight sucks ass, so shut up about it your retarded fanwhore"
Twilight fanwhore: "OMFG HOW FUKIN DAR U INSULT TEH GRAT GODESS STEFANIE MIYER I WIL FUKKIN KIL U!!11!"
*Twilight fanwhore proceeds to kick sane person in the balls*
Sane person: "Twilight sucks ass, so shut up about it your retarded fanwhore"
Twilight fanwhore: "OMFG HOW FUKIN DAR U INSULT TEH GRAT GODESS STEFANIE MIYER I WIL FUKKIN KIL U!!11!"
*Twilight fanwhore proceeds to kick sane person in the balls*
by MISTER OWNINATOR December 22, 2009
a person who is such a big fan, they often dream of whoring themselves out to whoever or whatever it is that they are so fanatic about.
by Nick Steinmetz March 23, 2006