One who often finds himself in the middle of the battlefield collecting metal and building machines (such as teleporters) to help ensure victory. Arch enemy of the spy. Common phrases include; "Teleporter goin up" "Sentry goin up" and "SPY SAPPIN MY SENTRY!"
You: Hey engineer, keep checking your back. There's a spy around.
Me: Thanks, HEY, SPY SAPPIN MY SENTERY!