Definition of blowbacks:
(n) :
An unintended adverse result, especially of covert political action.
(n) :
(firearms) A type of action where the pressure from the fired cartridge blows a sliding mechanism backward to extract the fired cartridge, chamber another cartridge, and cock the hammer.
(n) :
(slang) The act of shotgunning (inhaling from a pipe etc. and exhaling into another smoker's mouth).
(n) :
(computing) Synonym of backscatter.
(n) :
(rail transport) On a steam locomotive, the reversal of exhaust gases when the regulator is closed without using the blower.