fall-out

Noun

fallout (countable and uncountable, plural fallouts)

1. The 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. The 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. A negative side effect; an undesirable or unexpected consequence.
   • Psychological fallout in the shadow of terrorism

   Synonyms:

   blowback, repercussions

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