To cancel ruthlessly and shamelessly with no or exceedingly little notice as often as possible. Excuse may or may not be plausible/honest. Grandma died again. Sick. Tired. Don't feel like it. Whatever the reason. You don't even need one.
Then agree to any future plans or offer new plans to cancel on later for further enjoyment and rejection reinforcement.
Synonymous with sadist.
Did you hear about John's date last week?
Yeah, the girl joanna'd on him for the third time.