Wild lionesses not making a sound (9)
I believe the answer is:
noiseless
'not making a sound' is the definition.
(I've seen this before)
'wild lionesses' is the wordplay.
'wild' is an anagram indicator.
'lionesses' is an anagram of 'NOISELESS'.
(Other definitions for noiseless that I've seen before include "with a silencer?" , "Lionesses (anag) - making no sound" , "unsound?" , "Mum" , "Silent, quiet" .)