look up any word, like half chub:
 
1.
OBS is when your guy-friend is wayyy too much like an older brother...overprotective, and hates anyone who touches you..or talks to you..or looks at you the wrong way. Sometimes as annoying as a sib, but you love them anyway:)
Guy: Hey gurl, wanna go out this weekend?

Girl: SURE!

Girls Best Guy-friend: Who is he? What does he want? Why is he talking to you?

Girl: Dude, chill it with the OBS (older brother syndrome)
by PIAFFE September 10, 2013