fallout

plural fallouts

1. countableuncountableThe event of small airborne particles falling to the ground in significant quantities as a result of major industrial activity, volcano eruption, sandstorm, nuclear explosion, etc.

   It was 5 February 2010 and Safdar had already dealt with the fallout of one explosion that day: an hour before, a motorbike laden with explosives had slammed into a bus carrying Shia Muslims to a religious procession.

   2017 April 6, Samira Shackle, “On the frontline with Karachi’s ambulance drivers”, in the Guardian

2. countableuncountableThe particles themselves.

   On 26 April 1986 the reactor number four at the Chernobyl Nuclear Power Plant located in the Soviet Union near Pripyat in Ukraine exploded. Further explosions and the resulting fire sent a plume of highly radioactive fallout into the atmosphere and over an extensive geographical area.

3. countableuncountableA negative side effect; an undesirable or unexpected consequence.

   Psychological fallout in the shadow of terrorism

   Synonyms: blowback, repercussions

4. countablerareuncountableA declined offer in a sales transaction when acceptance was presumed.
5. countablerareuncountableThe person who declines such an offer.
6. countableuncountablebroadcastingAn impromptu guest used to fill in for another guest spot who is a no-show or who has cancelled last minute.