coulrophobia

An unusually strong fear of clowns.

Try an Internet search for coulrophobia and you'll turn up a host of sites by coulrophobes, such as the
very creepy creepyclown.com and ihateclowns.com.

Reportedly coined in the 1980s, coulrophobia derives from the Greek kolobathristes, which means
"one who goes on stilts".

From Martha Barnett's Fun Words:
http://www.funwords.com/library/c.htm