Rain in ruin? (8)
I believe the answer is:
downfall
I believe this is a double definition.
'rain' is the first definition.
(I have seen 'heavy rain' mean 'downfall' so perhaps 'rain' could also mean 'downfall')
'ruin?' is the second definition.
(I know that ruin can be written as downfall)
'in' acts as a link.
(Other definitions for downfall that I've seen before include "Failure (after successful career?)" , "state of ruin" , "Cloudburst" , "heavy rain" , "Collapse, ruin" .)