The word Wane means to decrease in vigor, power, or extent; to decline or diminish. It describes a gradual reduction in size, strength, or intensity. Therefore, the most accurate synonym among the choices is Decrease (option B).
When something wanes, it gradually fades away or becomes smaller. A classic example is the moon, which “waxes and wanes,” meaning it grows larger and then smaller. Similarly, enthusiasm might “wane” over time, or a trend might “wane” in popularity. Option A, “Increase,” is an antonym, meaning to grow larger or more intense. Option C, “Grow,” and Option D, “Expand,” also imply an increase in size or scope, making them antonyms. Understanding “wane” is useful for describing processes of gradual decline or reduction, whether in physical size, emotional intensity, or influence, highlighting a natural progression towards diminishment.