A not-boyfriend. A boy who'll spend all his free time with a girl, shag her loads, say lovely things to her, even go on holiday with her - but then vociferously deny that anything is going on between them, even though it appears to the outside world as if they've having a relationship.
N.B. Girls can also do this to boys, but it seems to be more common the other way round.
"Well - when they're out in public he'll pretend he's not with her, so he can scope out other girls, but they spend all their time together, and it's obvious they really like each other. He's totally noyfriending her."
Someone who does not obsessively try to see how many "friends" they can acquire on websites with a "friending feature" (such as MySpace, Facebook, LiveJournal, Red vs Blue and all other websites with such a function.)
"I pride myself in nonfriendwhoreyness!" said the non-friendwhore.
The act of neither confirming nor ignoring a facebook friend request, thereby leaving the friend request that is "awaiting confirmation" hovering in your friend request box indefinitely, leaving the requester completely powerless.
Janie: Hey, did you ever respond to that friend request from Kathleen?
Elena: No way! I totally nonfriended her. She can keep waiting.
Janie: Nonfriending is the only way to go with that crazy bitch. You wouldn't want her to facestalk you anyways.