Disaster affected cat, dog and fox losing tail (3,2,3)
I believe the answer is:
act of god
'disaster' is the definition.
(I have seen 'Natural disaster' mean 'act of god' so perhaps 'disaster' could also mean 'act of god')
'affected cat dog and fox losing tail' is the wordplay.
'affected' indicates an anagram.
'and' means one lot of letters go next to another.
'losing tail' means to remove the last letter.
'fox' with its final letter taken off is 'fo'.
'cat'+'dog'='catdog'
'catdog' after 'fo' is 'focatdog'.
'focatdog' with letters rearranged gives 'ACT OF GOD'.
(Other definitions for act of god that I've seen before include "Event beyond human control" , "Uncontrollable natural event like earthquake" , "Event not caused by human error" , "naturally a disaster?" , "Inescapable happening" .)