noun: Italian or Italian-American who is born with genes to know it all and to be correct in all things, all the time.
Has strong integrity in all things he/she does and will not back down on opinion. DeMaios usually bear distinct facial features, i.e. large nose, full lips. Though respected as they mature, some young opinionated DeMaios may not achieve success in the career of choice, due to lack of business manners and the know-it-all attitude, also known as "not knowing when to shut up".
see: mouth almighty, tongue everlasting
She must be a DeMaio, she knows it all.
You can tell he's got a lot of DeMaio blood, he's right ALL the time and knows all things! Just ask him!
He's all DeMaio. Big mouth.