When a guy or girl likes somebody, and they're serious about trying to get with that person. So they talk to them, try to make them laugh, spend as much time with them as possible. Their intention usually is to make friends with that person until they build the confidence to ask them out.
What's sad about a self-rejection is, that person loses the confidence to ask them out (or they discover or think they're already going out with someone and feel there's no point in trying to build-up a future relationship). Basically they're scared of rejection.
This person can never know that they were liked, going to be asked-out, so it's a real downer when they find out somebody gave up on trying to get with them (especially if it's a pretty depressed person)
Self-rejections usually occur in low confident/self-esteem teens during their middle/high school years. Usually self-rejections hurt more than actual rejections from the person, because you feel that maybe, they would say yes. You didn't even give yourself a chance.
A self-rejection is not seeing someone in the hallway, thinking they're cute, and not talking to them and giving up. You actually try to build up a friendship with that person and give up.
A self-rejection is also not, asking out a someone, still liking someone, maybe asking them out again, and giving up. Because with this, you built up the courage to ask to ask them out.
Even though the person you were trying to ask out, didn't say "no" (you didn't ask them out period), but you say "_______ self-rejected me", which basically means you gave up on that person.
After so many self-rejections this person may feel they're never going to find somebody. The best advice for that person is to try to build them up and make them a confident being, and they might ask that person out and be happy!
EXAMPLE OF SELF-REJECTIONS:
Tony was talking to Alicia all month. He couldn't get her out of his head! He really liked her. Until one day he stopped talking to her, and she didn't know why. She knew about how he was a pretty un-confident person, so she wasn't suprised when she found out she self-rejected him.
NOT A SELF-REJECTION:
I see him walk by every day before study hall, he's so cute, but I should probably stop and try to get someone else.
Roy asked her out last year, even though she did like him, she had a boyfriend. He was confident enough to ask her out again, even though this time she had a different boyfriend. He gave up and is just friends with her now.