A person who uses drugs or is habitually silly; one who deals with or knows about dope (either drugs or information).
From 'dope' plus '-ster' (suffix indicating a person associated with something). Similar to how 'hipster' and 'trickster' work.
The '-ster' suffix is fun because it often suggests someone has made an identity out of something—a dopster isn't just someone who uses dope, they're defined by the culture around it.
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