The word "un-initiated" means someone who is not familiar with a certain subject or knowledge. The antonyms for un-initiated could be initiated, knowledgeable, informed, aware, educated, experienced, comprehending, and familiar. Being initiated refers to knowing the basics of a particular topic and having knowledge about it. An individual who is knowledgeable has comprehensive information and understanding of a subject. Being informed refers to having knowledge about the latest developments, whereas experienced implies having a practical understanding of something. Comprehending applies to the extent of understanding a particular topic. In other words, these antonyms for un-initiated describe someone who is familiar with the subject and has adequate knowledge to talk about it.