An irrational fear of cannabis that was mostly caused by traumatic memories which could be results of many years of prohibition. As an illegal drug, cannabis was closely related to shady characters selling all range of drugs, who considered "converting" cannabis users to harder drugs (i.e. amphetamine, cocaine) profitable.
This is also the source of "gateway theory", which states that smoking cannabis leads to harder drugs usage.
Someone: Dude, I tried everything! I showed my dad all the infographics, test results, detailed story of cannabis criminalization... How can he be so stubborn?!
Someone Else: Give up, mate, your dad is a total cannophobe. Now pass that joint...
Someone: He's a who?
Someone Else: He has a bad case of cannophobia. Will you pass it or not?
Just Fucking Dies Laughing
You: I'm sick of all those LOL, ROTLF, LMAO and shit