To discover or establish conclusively明确地决定或建立To win赢得
fight tooth and nail
见 tooth
hard as nails
(of a person) very tough; completely callous or unfeeling（人）强硬的；铁石心肠的，冷酷无情的
nail one's colours to the mast
a nail in the coffin
an action or event regarded as likely to have a detrimental or destructive effect on a situation, enterprise, or person催命符，致命一击
on the nail (北美亦作
(of payment) without delay（付款）当场的，立即的
nail someone down
elicit a firm promise or commitment from someone使承诺
nail something down
fasten something securely with nails钉牢，钉住identify something precisely弄清，确定secure something, especially an agreement敲定；确保（某事物，尤指协议）
nail something up
fasten a door or window with nails so that it cannot be opened把（门、窗等）钉死
英语四级真题
In response to those restrictions, grain-importing countries are trying to nail down long-term trade agreements that would lock up future grain supplies.
出自-2016年6月阅读原文
英语六级真题
fighting back the tears, he spoke proudly of the fact that he had built their home from the ground up, and that he had pounded every nail and laid every brick in the process.
2015年12月六级真题（第一套）听力 Section C
柯林斯高阶英汉双解学习词典释义
N-COUNT
钉子
A nail is a thin piece of metal with one pointed end and one flat end. You hit the flat end with a hammer in order to push the nail into something such as a wall.
If you say that someone is as hard as nails, you mean that they are extremely tough and aggressive, either physically or in their attitude towards other people or other situations.