When a dude has a ponytail, but he is butt-ugly, not very sexy, and/or the ponytail is extremely unkempt.
"Ew, look at that guy. That's a ponyfail."
by nongenerica January 03, 2010
1 more definition
A ponytail made with no regard for style.
He just bough a Miata and he's sporting a ponyfail - must be a mid-life crisis.
by cranston snord July 12, 2008