Completely dark; pitch-black — a state with little or no light.
停電で家の中が真っ暗になった。
A power outage plunged the house into pitch darkness.
夜道は街灯が少なくて真っ暗だ。
The road at night is very dark because there are few streetlights.
カーテンを閉めたら部屋が真っ暗になった。
When I closed the curtains, the room became completely dark.
Figuratively, bleak or hopeless — used to describe a very uncertain or dismal outlook.
会社の業績が悪く、この先は真っ暗だと噂されている。
The company's performance is poor, and there's talk that the future is bleak.
借金が重なって生活は真っ暗になった。
Debts piled up and life became hopeless.