White Knight Syndrome, often shortened to WKS, is what many lonely internet males (usually virgins) get when consulted with anything to do with a girl.
However, this person does not have to of seen the girl or even conversed with her in any way to stick up for her. If there is a topic about a male and a female, those suffering from WKS will always side with the female in the hopes of getting laid.
Guy 1: Dude, she lied and said she was on the pill and convinced him not to wear a condom, how is it all his fault she got pregnant?
White Knight: He's the one with the penis, he's the one who came inside of her, it's all his fault!
*White Knights thoughts*: Now girls will want to fuck me!
Guy 1: Whatever dude. By the way, I'd go see the doctor about your White Knight Syndrome.