A meaningless but more exciting variation on the "yes/no?" question. Popularized by Gan Xingba's Avatar: the Abridged Series.
Can be abridged as "y/n/m/l?", but chances are, if your friend is not a hardcore Avatard, s/he will have no idea what the fuck that you're talking about and get confused.
When a guy asks a girl out and she tells him yes, but really means no because she's too nice to say no, which in turn messes with him more because he continues to think he has a chance, but really doesn't.
"Wanna go out with me this weekend?"
"...Yes."
"So are you twogoing out?"
"I dunno, she's being all gay and withdrawn, I think it's a yes-no."