Eidolons are defined as idealized or phantom-like images, but what are their antonyms? Antonyms for eidolons would be reality, actuality, substance, concreteness, tangible, and real-world experience. Eidolons are often associated with something that is not real or concrete, making their antonyms the opposite, which are things that are grounded in reality or can be experienced physically. So, we could say that eidolons and their antonyms form a binary, a dichotomy between the imaginary and the tangible. Therefore, depending on the context, the antonyms for eidolons would be the concrete, the real, and that which we can touch and perceive with our senses.