A pretend boyfriend invented for the purpose of deterring undesirable romantic attention.
Sally got annoyed that, even though she continually turned him down, Brian would not take the hint and stop asking her out. So she made up a "faux beau" in the hopes that Brian would finally leave her alone.
An imaginary boyfriend, usually a celebrity. This crush is characterized by the obsessive consumption of the individual's body of work (whether in music, film, television, etc), no matter how terrible or lame it is.
"My new faux beau is Paulie Jr. from "American Chopper"; it's the stupidest show on TV, but I could watch him read the phone book."