an acronym that stands for a "No-Apparent-Reason-Boner", often occuring among middle-schoolers and sometimes high-schoolers. the N.A.R.B. can be hidden if one knows the proper techniques
Dude i got a wicked narb in english class today.
My sweat pants are revealing my enormous NARB.
The word Narb means no apparent reason boner. I had such a huge throbbing narb today!