Like the proverbial period before a storm

CALM

Think of the opposite of chaos, often described as a serene moment in nature—like a lake with no ripples.

This clue references the common phrase "the calm before the storm," which describes a quiet or peaceful moment right before chaos or trouble begins. The word "proverbial" signals that it’s a well-known saying, so the answer is simply the adjective that fits: "calm." No wordplay here—just a straightforward nod to a familiar idiom.