What is the word describing self taught?

There isn't one single perfect word, but several options depending on the nuance you want to convey:

* Autodidact: This is the most formal and precise term for a self-taught person.

* Self-taught: This is the most straightforward and common phrase.

* Unschooled: This implies a lack of formal education, which may or may not be self-directed learning.

The best word to use will depend on the context.