Doesn't that song drive you bananas? The incessant beat, the stomping, the shushed-out swear words, and just what the heck is Gwen Stefani talking about? We don't want to get everybody fired up, so we put our pom-poms down and tackled this most important inquiry. After a few times around that track, we discovered what a Hollaback Girl is and why Gwen ain't one.
The OC Weekly's insightful analysis points to cheerleading as the source of the slang. The cheerleading captain 'hollas' a chant to the squad, and the girls 'holla' it back. So the hollaback girl is a follower, and by extension, she is treated like a doormat, especially by boys. Writers on the Urban Dictionary add that a hollaback girl is all talk, no action, and won't fight back.
Obviously, Gwen is gonna fight and give it her all. She even socks it to us by proudly confirming her cheerleader roots. And while similarly a cheerleader at heart, Toni Basil doesn't appear to be a hollaback girl either.
source: http://ask.yahoo.com/20060414.html