doornail的意思？

doornail的音标：doornail的英式发音音标为：['dɔ:neɪl]doornail的美式发音音标为：['dɔrneɪl]...

Times are bad, the market is dead as a doornail.时势不好, 市面清得不成话.It lay there with its eyes closed, dead as a doornail.它躺在那里眼睛闭着, 确实死了.The treaty may be considered to be as dead as a doornail.这项条约可以认为是完全作废了....