Things people do that may make others believe they are on crack or other drug(s) which would explain such stupidity.
Dude, my sister just got back with her boyfriend again after that fool stole her money, crashed her car, and screwed around on her. Response: Damn dude, that's some crackfoolishness.
A person who has smoked crack cocaine for many years, decades even. So much that they have made it a career to smoke rock. They are experts in the field of crack smoking.