illiterate

Short definition from Wiktionary

Adjective

1. 1
   Unable to read and write.
2. 2
   Having less than an expected standard of familiarity with language and literature, or having little formal education.
3. 3
   Not conforming to prescribed standards of speech or writing.
4. 4
   Ignorant in a specified way or about a specified subject.

Noun

1. 1
   An illiterate person, one either not able to read and write or not knowing how.
2. 2
   A person ignorant about a given subject. (The relevant subject is usually named as a noun adjunct.)