na-adjective, noun
unconscious; blacked out; having no memory of one's actions
Describes a state of being so intoxicated, injured, or overwhelmed that one loses consciousness or later cannot recall what happened. Often used with ～になる or ～の状態.
彼は酒を飲みすぎて前後不覚になった。
He drank too much and blacked out.
事故の衝撃で前後不覚の状態だった。
I was unconscious from the shock of the accident.