The phrase "most nonresonant" refers to something that does not produce a strong resonance or vibration. There are several words that can be used as synonyms for it, such as inharmonic, discordant, unmelodious, dissonant, unharmonious, atonal, and cacophonous. Inharmonious refers to something that lacks harmony due to conflicting elements, while discordant refers to sounds that clash or do not blend well. Unmelodious and dissonant refer to sounds that are unpleasant or grating to the ears, and unharmonious refers to something that is not harmonious or lacking agreement. Atonal refers to a lack of tonal center, and cacophonous refers to a harsh and unpleasant mixture of sounds.