Hubble-bubble is a term used to describe the sound of boiling or bubbling water. It is often used in reference to a noisy or chaotic situation. Antonyms for hubble-bubble include peace, quiet, stillness, calm, serenity, and tranquility. These are all words that describe a situation or environment that is peaceful and calm, without any noise or disturbance. Hubble-bubble can also be used to describe a confusing or messy situation, so antonyms for this sense of the term might include clarity, organization, order, and structure. Ultimately, the opposite of hubble-bubble is a calm and ordered environment, free from chaos and confusion.