A circular form of continuous headbanging, demonstrated by only the most metal of metal bands.
I saw Decapitated last night, that was some hairnado inducing metal.
by caralizabeth June 12, 2007
A pubic phenomenon of massive growth. This happens when the hair on the external pubic region is in excess of the available surface area, thus forcing the growth into a turbulent swirling tornado of hair and debris.
Once I saw my date's hairnado, I had to run for cover in the basement!
by Yoga Mom August 15, 2011