Nonresonant refers to something that doesn't vibrate or produce a sound, hence antonyms for nonresonant should reflect qualities that imply resonance, noise or sound. Possible antonyms for nonresonant are resonant, harmonious, vibrant, sonorous, melodious, musical, tuneful, rhythmic, pulsating, and echoing. Resonant describes something that produces rich, deep, and clear sound waves, while harmonious refers to sounds that are harmonious, in agreement or accord, and pleasing to the ear. Vibrant, sonorous, melodious, and musical all imply pleasant, resonant or musical sounds, while tuneful and rhythmic refer to pleasing or harmonious melodies or beats.