Which word describes something that causes sleep?

The term "soporific" specifically refers to substances or agents that induce sleep or have a sleep-inducing effect. It is derived from the Latin word "sopor," meaning deep sleep. When something is described as soporific, it typically implies that it has a calming or sedative effect, often used in contexts related to medicine, like sleep aids or certain medications that are prescribed to promote rest.

In contrast, the other options describe qualities that are the opposite of inducing sleep. For instance, words like "arousing" and "stimulating" convey a sense of excitement or heightened alertness that would typically keep someone awake. Similarly, "inspiring" and "energizing" suggest an invigorating effect that promotes activity and engagement, while "reviving" and "refreshing" imply a restoration of energy or alertness—a quality that would not contribute to sleepiness. Thus, the only option that directly conveys the concept of causing sleep is "soporific."