The RATIONAL fear of clowns. Commonly and justifiably used to describe one's fear and disgust with yellow- or green-toothed humans, hiding behind white face paint and other heavy makeup.
Poncho: Hey daddy, can we go to the circus?
Daddy Mark: Sure, as long as we stay away from those creepy and disgusting clowns!
The rational fear that Colonel Sanders is always watching you, ready to end you with his double-barreled shotgun if you insult KFC or him in any way.
"Dude, I got such colonelphobia when I told mother that I didn't want the crappy biscuit that came with my three-piece, so I immediately looked around and apologized out loud."