doper

noun3

1. •
   (offensive) One who frequently uses recreational drugs; a druggie; a stoner.

   • That crafty old doper breaks out a "stick" of "tea" and they sit in the sun handing it back and forth, offering the waiter a hit... — 1973
2. •
   (disapproving) One who uses performance enhancing substances for competitive gain, especially illegally.

   • Would you care to point to some proof other than the Canuck's positive back in Nagano? If you are using that as a basis then all sports would be riddled with "dopers" especially XC skiing. — 2003
3. •
   (old-fashioned) A person employed to apply dope solution during aircraft manufacture.