Countdown Girl - A female that looks good from a distance, but her appearance becomes progressively worse upon approach.
"I thought she was hot, but she ended up being a Countdown Girl."

"What do you mean a countdown girl?"

"I thought she was a 10, but as I was walking up to her she turned into a 9...8...7...6..."

*Hysterical Laughter*
by Dee Wayne December 8, 2009
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An attractive female who studies maths or has a degree in it.

However it can generally be used to describe any attractive and intelligent girl.
"Brooo, you see that fit girl walk out of science class?" Damn she's a proper countdown girl"
by shitsplatter September 21, 2013
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A person that every time you see them their Hotness level drops, beer or any other such judgment imparting drink or substances not involved
Dude, she is a countdown girl, yesterday she was a 10 and today shes a 9, who knows how far she will fall.
by CisforCookie December 10, 2007
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