One who has an affinity for all things relating to cannabis. Can be a synonym for a cannabis connoisseur. A cannabist is essentially more than a marijuana smoker, he or she is a marijuana enthusiast. A cannabist can often be spotted with his nose in a baggie of bud for long periods of time, or examining a nugget or brick of hash up close with a magnifying class as if it was a piece of jewelry. Most cannabists are familiar with most aspects of cannabis culture-- breeding, growing, smoking, rolling, smoking device construction, etc. Some may contend a cannabist is nothing more than a marijuana geek.
"Your boy that calls himself a cannabist talks way too much about weed. Every word that comes out of the dude's mouth is about some strain or another. What a buzz kill..."
Someone who hates the use, and/or the people that use cannabis. Their feelings towards marijuana users are similar to a racist's or sexist's feelings towards another race or the opposite sex.
Jeff: Sorry bro, no more blazin' in my dorm.
Adam: (sets down the piece, obviously upset) why not dude?
Jeff: Its my new roommate. He's a real cannabist