Hide from onset of this during terrible soaking (8)
I believe the answer is:
goatskin
'hide' is the definition.
(goatskin is a kind of hide)
'onset of this during terrible soaking' is the wordplay.
'onset of' suggests taking the first letters.
'during' is an insertion indicator.
'terrible' is an anagram indicator.
The first letter of 'this' is 't'.
'soaking' anagrammed gives 'goaskin'.
't' inserted within 'goaskin' is 'GOATSKIN'.
'from' acts as a link.
(Other definitions for goatskin that I've seen before include "Leather from nanny or billy?" , "Type of leather - a song kit (anag)" , "Billy's hide?" , "Hide Billy or Nanny" , "Leather - wine holder of old" .)