Definition of blacking out in English:

blacking out

noun

  • 1The action of covering something with black; the action or an act of obliterating or obscuring something.

  • 2The experience of having a blackout, especially of being rendered unconscious; the occurrence of a blackout; an instance of this.

Origin

Late 18th century. From black + -ing + out, after to black out.

Pronunciation

blacking out

/ˌblakɪŋ ˈaʊt/