a person who has learned a subject without the benefit of a teacher or formal education; a self-taught person.
Origin: 1525–35; < style="font-style:italic;">autodídaktos self-taught
autodidact. Dictionary.com. Dictionary.com Unabridged (v 1.1). Random House, Inc. http://dictionary.reference.com/browse/autodidact
One of the many words I use to define myself.