A player who use trainers to cheat in games. They are not "hackers", hackers are people with real skills. Trainer boys are often noobs, who use programs made by hackers in an attempt to piss other players off.

Also known as T-Kiddies
A: "There was a trainer boy in the other server so I left. I hate T-kiddies"
B: "yeah, I hate noobs too."
by TonyZee April 11, 2008
Get the trainer boy mug.