The word "boisterous" describes something that is noisy, lively, and full of energy. To find its antonym, we need to look for a word that represents the opposite qualities, which would be something calm and quiet.

 "Quiet" implies a lack of noise but doesn't necessarily convey the same sense of peacefulness and stillness that "calm" does. "Calm" captures both the absence of noise and a sense of tranquility.

Option 2: Like

"Like" is not an antonym of "boisterous." It is a comparative term and does not relate to the concept of noise or liveliness.

Option 3: Noisy

This is not an antonym but a synonym for "boisterous." Both "boisterous" and "noisy" convey similar ideas of something being loud and full of commotion. Therefore, it is not the best choice for an antonym.

Option 4: Calm

When something is calm, it is not noisy or tumultuous, which is the opposite of boisterousness. This is the best antonym for "boisterous" because it signifies a state of tranquility, serenity, and the absence of noise and commotion.

While "quiet" is a reasonable choice, it may not be as strong an antonym as "calm."