The act of attracting large amounts of guys, usually unwanted. Guys that are attracted are usually guys that girls thought were uninterested, but turn out to be hardcore crushing. This is not to say that "Guynips" are hot, though that is a big part. Guynips are generally outspoken and confident.
Guy: Hey, do you want to go out?
Girl: What?!? I thought we were just friends!
Guy: I can't help it: You're a Guynip.
Girl: What?!? I thought we were just friends!
Guy: I can't help it: You're a Guynip.
by Spikey Vampire Hair August 6, 2010
(N) Any garment, item or behavior that excites, beguiles or otherwise entices guys; anything that has the same effect on men that catnip has on cats.
If you want to attract a guy, try an little black dress and some red lipstick: they're killer guynip.
by CCCW April 6, 2008