1. Someone that is on meth/speed
2. Someone could be called one for talking alot, pacing or moving alot or doing a task with an unusual amount of persistence, most of the time at unusual times late at night/early morning
3. You wont catch this person sleeping or eating. all though the food still looks good..
"Hey man uve been cleaning them rims for like six hours now and your on the second wheel, You tweakin?" (this is at 6 in the morning on a saturday after staying up all night, He sure was.)