Creatures made up by Luna Lovegood from the Harry Potterbooks. They are known to live in mistletoe, and they are quite the little theves. Sometimes, Nargles are used in Draco/Luna fanfiction.
Luna: When we were five, you told me that mistletoe had nargles in them.
High school (and sometimes college) boys who like sports, are generally huge assholes, get really drunk, say things like "damn son!", and are disrespectful to girls.
Typical nardy conversation:
Nardy 1: "Dude, I was so drunk last night!"
Nardy 2: "I know. I fucked insert random girl"
Nardy 1: "Damn son! Who was it?"
Nardy 2: "You know, just some bitch."
Typical girl conversation:
Girl 1: "Hey, I'm having a party tonight."
Girl 2: "Ew, can we not invite the nardies? I'm actually trying to have fun."
Steve: Hello Shmuley...
Shmuley: The fuck did you just call me?
Steve: You heard me.
Shmuley: Look Steve...getting accidental mom boob is one thing, but getting accidental mom forehead brushed on your hangsters is going too far. I won't stand for it!
Steve: Your mom stood for it.
Shmuley: Steve, I now have no choice but to get your mom to accidentally handle my nardledangers. Get ready, pal...your mom's gonna touch more sack than a medieval grain merchant on inventory day!