A "goomba" can mean "gangster" or "idiot"or a really close friend and a great guy." It's all a matter of how you say it, so you have to be careful. We like Steven Schirripa's  (Bobby Bacala of The Sopranos) definition best....
Goomba Stereotype vs. A Really Great Guy - the Guy You Can Trust in Business and Friendship
So What's a Goomba?
The stereotype is a guy at a social club drinking expresso, playing cards or eating a big plate of soggy macaroni with a napkin tucked into his collar. He usually wears gold chains. He wears a warm-up suit or baggy black pants and patent leather shoes.
Other Italian Words, Expressions and Definitions
Italian Smoking Jacket
A white tank top t-shirt commonly referred to as a wife-beater.
scarol or scharole
Italian slang for money
Italian princess
A female, of partial or full italian descent, who defines herself/flaunts her nationality in an obnoxious, ethnocentric manner. May be called a "guidette" or "guido girl". She has italian reflector stickers on her $30,000 car which her parents paid for. Wears "Italian Princess" tank tops. Is frequently covered in Juicy Couture, carrys Louis Vuitton bag(s) and wears Chanel/Gucci shield sunglasses or mirrored aviators.
Someone not of Italian descent who is trying to speak Italian badly.
Italian slang for 'the evil eye.' Basically it has similar meaning to the stink eye, but is scarier because it is given by evil little Italian women who then damn you for eternity for doing them harm, doing their family harm, or going against their will.
Italian frisbee
Italian slang for pizza.
Dennis DeMaio
Italian slang for a "know-it-all."
Italian slang for another Italian - never to be used by a non-Italian or it is an insult.
Check out more definitions here.
Copyright, Paisons on the Town, 2010 by InfinitelyKreative.com

"A true goomba will never let you pick up a check. You're the guest. He'll kill you before he'll let you pay....He's not a gangster. He's not a wise guy, or a member of the Family - but he knows those guys....He's Italian through and through.
It started from the word "compadre," a term of respect. It can be your godfather or your protector. And to most Italians today, a true goomba is a great person. The important thing is he's got a great heart, is a true friend, and treats you like  family.