: a person who frequently or habitually uses illicit drugs
He was a doper. He was loaded right now. Speed maybe. Or coke. Joseph Wambaugh
b
: a person who sells illicit drugs
"Dopers are right on the cutting edge of technology," says Jimmy Davis of the Georgia Bureau of Investigation. "It used to be that you weren't a certified dope dealer unless you had a beeper. Now you're not a big-time dope dealer unless you're cellular." Terry E. Johnson et al.
2
informal: an athlete who uses performance-enhancing substances typically banned for use in sports
Already athletes from Great Britain and Australia who finished behind drug-using East Germans have begun asking Olympic officials to disqualify the dopers and rewrite the record books accordingly.Sports Illustrated
Human growth hormone is another protein, already widely abused by dopers, that builds muscle and aids recovery.Bicycling