There are several words that can be used as synonyms for the phrase "everlasting noise". Some of them include continuous sound, endless clamor, incessant racket, and perpetual din. The word "eternal", meaning forever, can also be used as a synonym to emphasize the never-ending nature of the noise. Additionally, words like "unstoppable" or "unrelenting" can be added to emphasize the intensity of the noise, while words like "debilitating" can be used to describe the negative effects that an everlasting noise can have on a person. Ultimately, the choice of synonym will depend on the context and desired impact on the reader or listener.