A boy who is a complete and total ass. Likes to get stoned, party, fight and ride motor bikes. Usually is a player, and will cheat on any girl and every girl. Also tends to be a huge source of drama. Often asks females for topless picture on his cell phone. He wont take “no” for an answer and tends to harass you. Rios are also usually compulsive liars and will tell you what ever he thinks you want to hear. A Rio may also be used to describe a guy who dated a girl until she cheated, then took her back and knocked her up.
Remember never trust a Rio.
"Dude I cheated on Sarah"
"DUDE! THATS SO RIO!"
Boy:"Heyyy, can I get a pic ;]"
Girl:"No, sorry hun. I got a man"
Boy:"Come on i want one really baaaad. And im better"
Girl:"Your being such a Rio"