Silent river creatures start to struggle around wintry weather (9)
I believe the answer is:
voiceless
'silent' is the definition.
(thesaurus)
'river creatures start to struggle around wintry weather' is the wordplay.
'river creatures' becomes 'voles' (creatures who live by rivers).
'start to' indicates taking the first letters.
'around' indicates putting letters inside.
'wintry weather' becomes 'ice'.
The initial letter of 'struggle' is 's'.
'voles'+'s'='voless'
'voless' going around 'ice' is 'VOICELESS'.
(Other definitions for voiceless that I've seen before include "Dumb" , "Mum" .)