the backward escape of unburned gunpowder after a shot
- the backward escape of fumes and unburned gunpowder after a gun is fired
- misinformation resulting from the recirculation into the source country of disinformation previously planted abroad by that country's intelligence service
additionally blow-back, 1883, in reference to flames in enclosed areas (guns, furnaces, etc.), from blow (v.1) + straight back (adv.). Feeling in reference to transform actions, etc., is from 1978.