look up any word, like pretty face challenge:
 
1.
a non boyfriend boyfriend, is a really close boy that you've been seeing for awhile and basically are dating, but don't have the relationship status
been seeing one guy for 6 months or more, go out, spend all free time together, hug, kiss, sleep together, just he isn't your 'boyfriend' so he's the non boyfriend boyfriend
by Robyn V. April 29, 2008
 
2.
The male part of a relationship that, for all purposes, are boyfriend and girlfriend, yet the couple refuses to acknowledge it or use the label.
M: Hey, are you and your boyfriend coming to my party on Saturday?
V: He's not my boyfriend!! But yeah, we'll be there, after dinner with his mom.
M: Oh yeah, sorry, your non-boyfriend boyfriend.
by MadisonG November 03, 2010