"Wert proxy for" is an idiomatic expression that means "to serve as a substitute for." The word "proxy" in this context refers to someone or something that stands in place of another. Antonyms for "wert proxy for" would include words like "original," "authentic," "genuine," and "real." These words describe something that is not a replacement, but the real thing. Other antonyms may include "unique," "distinct," "individual," "singular," or "irreplaceable," which describe qualities that cannot be replaced by something else. Using antonyms for "wert proxy for" can add depth and clarity to language, and help to convey more precise meanings.