A lightly usedinsult referring to someone who is being a noob and you are calling them a scrub.
Person 1: "Hey guys! In Super Smash Bros, throw off the ledge to down smash spike is a true combo!"
Person 2: "Your such a nubscrub. That's impossible."
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi