* Real: This is a general antonym that means something that actually exists.
* Actual: Similar to "real", this implies something that is true and verifiable.
* Concrete: This implies something that is tangible and physically present.
* Factual: This refers to something based on facts and evidence.
* True: This emphasizes the authenticity and accuracy of something.
The best choice will depend on the specific situation. For example, if you're talking about a character in a story, "real" might not be the best choice, while "true" might be more appropriate.