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Verb. To do that which is both unnecessary and uncalled for, for the purpose of self-amusement. Always has a victim, often oneself.
Head-butting that guy on a whim was definitely Castaldoing.
by Bruce Thomas April 04, 2010
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Jun 24 Word of the Day
An exclamation made when your friends or family are teasing you to a point where you can't handle it anymore and a hissy fit is in order.

Derived from a YouTube user's famed outburst following Britney's lackluster performance at the 2007 VMA's.
Sarah: 'OMG Susan, I can't believe you are wearing the same skirt as yesterday. Oh, and by the way, EVERYONE knows what you did with Kevin on the weekend. Plus you look a little fat, are you retaining water?'

Susan: 'LEAVE BRITNEY ALONE!'
by Billy Chickenhole September 15, 2007
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2
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."
by CliveChurchMusic May 23, 2010
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