Don sat, cardigan’s spoilt, going to be terribly wet (4,4,3,4)
I believe the answer is:
rain cats and dogs
'be terribly wet' is the definition.
I can't tell whether this defines the answer.
'don sat cardigan's spoilt' is the wordplay.
'spoilt' indicates anagramming the letters.
'don'+'sat'+'cardigans'='donsatcardigans'
'donsatcardigans' is an anagram of 'RAIN CATS AND DOGS'.
'going to' acts as a link.
Can you help me to learn more?
(Other definitions for rain cats and dogs that I've seen before include "To fall heavily" , "come down hard" , "bucket" , "Pour" , "Pelt" .)