susurrous

Susurrous derives from the Latin noun susurrus, meaning "a hum" or "a whisper," and may be a distant relative of swarm (think of the collective hum of a beehive). Susurrus is itself an English noun with the meaning "a whispering or rustling sound" (Stephen King provides us with the example of "a violent susurrus of air"). Both the noun and the adjective (note that the two are spelled differently) are products of the 19th century, but they were preceded by the noun susurration, which in the 15th century originally meant "malicious whispering or rumor." Today susurrous is used to describe any kind of sound that resembles a whisper: a light breeze through a tree, perhaps, or the murmurs of intrigued theatergoers.