blacking out
/ˌblakɪŋ ˈaʊt/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.