short for bishounen, which literally means beautiful boy or pretty boy in japanese. usually describing a guy who has effiminate features as well as a slight build.
not necessarily a negative or positive word, its all in context.
"aww! that guy is so cute! hes so bishy!"
"man! that guy looks like a chick! haha! iv never seen anyone so bishy!"
A term used by anime fan girls Otaku and Weeaboo, often as the term used for male anime characters, who the fangirl, wishes was real. Often there is a list kept, ranking every preferred anime male. The lists are often posted on sites such as Deviantart or facebook.
"Omg, him, he's totally going to be a bishy!!"
"My Bishy list is soo long now, I'm not sure but I may cut a few out."