To do that which is both unnecessary and uncalled for, for the purposes of self-amusement. Always has a victim, often oneself.
In order for something to be a genuine Castaldo, the thought process behind it must be made immediately before the act, but in a form of retroactive hypothesis. The idea is that before you perform a Castaldo, you think about how amusing it will be in retrospect, as opposed to how irresponsible and dangerous it is in the immediate future.
Origin; Italian-American - New Jersey.
"Yes, I'm leaving you with my car keys. Don't Castaldo like last time: It took forever to dig that hooker's fingernails out of the grill."
The Act of being to smart for your own good making every one around you feel stupid and insignificant, and there only purpose in life is to buy you food another trait of a cataldo is the act of buying shoes that are $300 and up and never washing your car this is being a Cataldo.
Don't mess with a Cataldo cause one day they will rule the world with dirty cars and expensive shoes.