Developed at
St.
Olaf College in Northfield, MN, NAF stands for "Non-Athletic Fuck". It can be used to refer to a person with zero athletic abilities, or someone who is clumsy or untalented. It can also be used as an adjective.
Johnny is
terrible at sports, he's such a NAF.
Did you
see that guy fall down the stairs? What a NAF.
That was a NAF throw, man.