A consistently recurring cough that appears only when a person smokes the chronic, or high-quality cannabis. The chronic cough sounds terrible, but is commonplace for the smoker.
Smoker 1: "Excuse me while I light my spliff."
Smoker 2: "Can I get in on that rotation?"
Smoker 1: "Sure, have a seat and and take a toke"
Smoker 2: (Smokes, coughs loudly and noticeably)
Smoker 1: "Are you OK? You sound like you're going to cough up a lung."
Smoker 2: (between coughs) "Oh yeah man, I've had the chronic cough for years."