1a. One that is a native of the borough of Manhattan, with intentions to continue living in Manhattan, alongside fellow boroughbreds, imports, and non-boroughbred New Yorkers.
1b. Young children that have already learned how to hail a cab at 9 months of age.
Adj. 2. Used to describe people who don't believe in the NYC subway system or walking more than a half-block to their destination; instead will employ the use of taxis--even if its to the next Starbucks up the street--or the one across from that.
Alex: "Yea man I go to Columbia University now. I decided to stay here since I've lived in NY all my life."
James: "Where are you from?--originally?"
Alex: Staten Island
James: "You're so not boroughbred..."