Short for 30 year old douche bag. A 30DB has the obnoxious attitude of a college frat boy / sorority girl, complete with the fake tan (and, in the case of the girls, the bug-eyed sunglasses). Now that he/she is all grown up, his/her Lacoste polo / Northface gear / boat shoes have been replaced as the "must have" item by the BMW/Mercades/Navigator that he/she drives (bought with Daddy's money, of course). The 30 DB female (also known as a douchette) is typically sighted carrying a tiny dog in her arms (a la Paris Hilton), and on the weekends she enjoys taking her little pooch to the dog spa & resort. The male 30DB generally opts for a larger, more masculine canine.
30DBs are particularly prominent in the Uptown neighborhood of Dallas.