A girl who from a distance of fifty yards away appears to be hot, but as you continue to approach you realize that many features that you could not previously see cause her to be in fact unattractive.
Alex to Jeff as they walk to class: Dude check out that blonde girl up ahead, I'm gonna get her number.
After they walk past without stopping to talk: Ok nevermind she was just a fifty yard fake out.
When a person looks exceptionally attractive from far away but as they are seen up close, are in fact, far from attractive.
"Damn that girl over there is hot!"
*Walks over to see her up close*
"Okay, take that back, she is butt ugly. Damn I hate fifty yard fakeouts!"