whispering in WordNet English dictionary

1. making a low continuous indistinct sound
   "like murmuring waves"; "susurrant voices"
   murmuring  susurrant  whispering 
   

1. a light noise, like the noise of silk clothing or leaves blowing in the wind
   rustle  rustling  whisper  whispering 
   
2. speaking softly without vibration of the vocal cords
   whisper  whispering  susurration  voicelessness