blow·back /ˈbləʊbæk $ ˈbloʊ-/ noun [uncountableU] 1 bad results of an action which were not intended We are now suffering the blowback of the terrible foreign policy choices made by the previous president.
2 the powder that is sent out when a gun is fired Other inconsistencies included the absence of fingerprints on the gun and of blowback material from the gun blast.