Here are some possibilities:
* Illiteracy: This is the most direct antonym, meaning the lack of ability to read and write.
* Ignorance: This suggests a lack of knowledge or understanding, which can be a consequence of illiteracy.
* Uneducated: This implies a lack of formal schooling or training, which can lead to illiteracy.
* Inarticulate: This refers to a lack of fluency or clarity in communication, which can be a consequence of illiteracy.
* Uninformed: This implies a lack of knowledge or understanding about a specific subject, which can be related to illiteracy in that area.
The best antonym will depend on the specific context in which you're using the word "literacy."