Open English Wordnet
Nouns
(n)rustle, rustling, whisper, whisperinga light noise, like the noise of silk clothing or leaves blowing in the wind
(n)whisper, whispering, susurration, voicelessnessspeaking softly without vibration of the vocal cords
Adjectives
(s)murmuring, susurrant, whisperingmaking a low continuous indistinct sound“like murmuring waves”, “susurrant voices”