fall ‧ out /ˈfɔːlaʊt $ ˈfɒːl-/ BrE AmE noun [uncountable]
1 . the dangerous ↑ radioactive dust which is left in the air after a ↑ nuclear explosion and which slowly falls to earth:
protection against radioactive fallout
2 . the results of a particular event, especially when they are unexpected:
The political fallout of the affair cost him his job.