An adjective used mainly by ignorant teenage girls to describe pre-determined, nonsensical words that are no longer funny.
Cynthia: "Oh my god! I am so random!"
Intelligent Marcus: "Oh really?" *rolls eyes*
Cynthia: "Yeah! I like dinosaurs! And monkeys! And ninjas! And condoms!"
Intelligent Marcus: "First of all, the plural form of the word 'ninja' is the same as the singular form. There is no such word as 'ninjas.' Second, that's not random. Half of that shit was stolen from your other friends on MySpace that are also NOT RANDOM. Third, you know what's really random? Glass jars manufactured in Mexico full of Komodo dragon semen. And Bill taping Nerf guns to his ankle. And radioactive ceramic electricity doing the Hokey-Pokey. That's random. Not fucking dinosaurs and squirrels and whatnot. Fuck off." *slaps Cynthia*