maybe it's just me

A not-negligible amount

I don't know if you've gotten hooked on any of the several singles from Gwen Stefani's solo thing but I kinda have & right now she's performing on Letterman with half a funky marching band ala Drumline & a troupe of tough looking asian dancers in half-cheerleader/half-Fly Girl get-up. I believe that this is one thing a person might be referring to when they say something is fierce.