olemus
(a) füüsiline, näiteks tulirelva puhul
(b) ülekantud tähenduses

Wiktionary:
1. (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
2. an unintended adverse result, especially of covert political action
Synonym: fallout

näiteid
https://en.wikipedia.org/wiki/Blowback_(firearms)
https://en.wikipedia.org/wiki/Blowback_(forensics)
https://en.wikipedia.org/wiki/Flapback
https://en.wikipedia.org/wiki/Blowback_(steam_engine)
https://en.wikipedia.org/wiki/Blowback_(intelligence)