About a thousand in Italy involved in disaster (8)
I believe the answer is:
Here is my best explanation:
'disaster' is the definition.
(I've seen this before)
'about a thousand in italy involved' is the wordplay.
'about' becomes 'ca' (abbreviation for 'circa'**).
'a thousand' becomes 'm' ('M' can be a synonym of 'thousand').
'in' indicates putting letters inside.
'involved' indicates an anagram (involved can mean confusing or complex).
'italy' with letters rearranged gives 'laity'.
'm' going into 'laity' is 'lamity'.
'in' acts as a link.
(Other definitions for calamity that I've seen before include "DISASTER]", "Martha Jane Cannary", "distress", "Tragedy", "Damaging event", "Great loss or misfortune", "Catastrophe", "Event resulting in great loss and misfortune", "A sad or disastrous happening" and "Disaster, extreme misfortune".)