Natures Clown 

A mentally retarded person

I work with a bunch of Natures Clowns.

Natures Clown by crackmsp March 19, 2008

nature clown 

One who is naturally funny. Has or pertains to having mental retardation and/or autism.

Guy 1: Did you watch Life Goes On?
Guy 2: No. I am afraid of nature clowns.

nature clown by Joel TK May 28, 2005