dead as a doornail

Adjective

(simile) Unquestionably dead. Used for both inanimate objects and once living beings.

Japanese Meaning

絶対に死んでいること、疑いの余地なく命がない状態 / 無生物やかつて生きていた対象の両方に対して用いられる比喩表現

When we found the old radio in the attic, it was dead as a doornail and wouldn't power on.

屋根裏で古いラジオを見つけたとき、それは完全に壊れていて電源が入らなかった。

Sense（1）

(simile) Unquestionably dead. Used for both inanimate objects and once living beings.

I picked up the phone, but the line was dead as a doornail.