Direct: This is the most common antonym, particularly when referring to someone acting on behalf of another.
Original: If you're talking about something being a proxy for something else, the antonym might be "original."
Real: If you're discussing a proxy as a substitute for something else, "real" could be an antonym.
Personal: If you're talking about a proxy as opposed to someone acting directly, "personal" might be an antonym.
Self: This is appropriate if you're referring to someone acting on their own behalf, rather than through a proxy.
Example:
* Proxy: "He voted by proxy, as he was unable to attend the meeting."
* Antonym (direct): "She voted in person, directly at the meeting."
It's essential to consider the specific context of the word "proxy" to choose the most suitable antonym.