Snake's sound (3)
'snake's sound' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for hiss that I've seen before include "Audio interference" , "Sharp sound of disapproval" , "Sound of serpent" , "Urgently whisper" , "Sound of escaping gas" .)
'snake's sound' is the definition.
(I've seen this in another clue)
This is the entire clue.