doper

Etymology 1

dope (verb) + -er

noun

1. (derogatory) One who uses performance enhancing substances for competitive gain, especially illegally.
   2003: Sam "I can't even explain what I'm feeling right now," says CLark in rec.skiing.snowboard 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.
   ...the testers are always in a race with the dopers and usually playing catch-up. 2006, Matt Seaton, Tour de farce, Guardian Unlimited
2. (derogatory) One who frequently uses recreational drugs; a druggie; a stoner.
   2003: Lt. John Hadily, ICE DESTROYS LIVES-TPD DOPERS IN DENIAL in talk.politics.drugs I will keep posting the fact that if you possess drugs where I am employed and you are caught I'll throw your sorry ass in a cage where the dopers belong.
   With the Kwik-Mart leveled by fire, Dante and Randal's professional aspirations take a southerly route to a Mooby's fast-food restaurant where dopey dopers Jay (Jason Mewes) and Silent Bob (Smith) have followed with their boombox and illicit activities. 2006, Gene Seymour, “Clerks II”, in Newsday
   2006:, Anthony Cormier, Father: 'We're here to find her body', HeradTribune.com Tamara Toy was a blue-eyed daughter of a preacher, growing up good and God-fearing but eventually getting lost along the way, falling in with dopers and felons and a petty crook who stole her heart.
3. (dated) A person employed to apply dope solution during aircraft manufacture.

Etymology 2

dope (adjective) + -er

adj

1. comparative form of dope: more dope