出自《史记·韩长儒列传》，用弩发射出的强有力的箭到了快掉下来的时候。比喻强大的力量已经到了衰竭的程度，不能再起作用，不值得害怕。弩：一种用机械力量射箭的兵器。末：尽头。
From the Biography of Han Anguogong in the Records of the Grand Historian. It refers to the point where great force is depleted and no longer effective or threatening – like a powerful crossbow bolt losing momentum near the end of its flight.
西汉时期，韩安国因为触犯刑律，被贬职为民。汉武帝登其后，韩安国通过贿赂宠臣田蚡，获得了北地都尉一职，不久后又升为大司农。后来韩安国在平定战乱中立了大功，汉武帝很器重他，每有军国大事，都要向他咨询。
During the Western Han, Han Anguogong violated criminal law and was demoted to commoner status. When Emperor Wu later took the throne, Han Anguogong bribed the influential eunuch Tian Fen to obtain the position of Northern Districts Governor, and soon after was promoted to Minister of Agriculture. Han Anguogong later made great contributions in suppressing rebellions, earning Emperor Wu’s high regard who consulted him on all important military and state matters.
有一天，匈奴突然派使者来求和。北方匈奴一直是朝廷头疼的问题，匈奴经常侵扰关边，朝廷发兵镇压也无济于事。现在匈奴突然提出求和的请求，汉武帝不能决断，于是就召来朝中大臣一起商议此事。很多大臣对匈奴厌恶透顶，坚决主张对匈奴继续用兵。
One day, the Xiongnu suddenly sent envoys to sue for peace. The northern Xiongnu had long been a headache, frequently raiding the borders despite the court sending troops to subdue them. With the Xiongnu now unexpectedly requesting peace, Emperor Wu could not decide and summoned his ministers for discussion. Many harbored deep resentment towards the Xiongnu and adamantly advocated continuing military action.
韩安国不同意他们的意见，他说：“派军队远赴千里与匈奴作战，很难取得胜利。匈奴目前兵马充足，又占有地利方面的优势，我们很难控制他们。况且强弩之末连鲁地所产的最薄的白绢也射不透；从下往上刮的强风，到了最后，连飘起雁毛的力量都没有了，并不是他们开始时力量不强，而是到了最后，力量衰竭了。所以发兵攻打匈奴实在是很不利的，议和才是上策啊！”
Han Anguogong disagreed, saying: “Dispatching troops thousands of li to battle the Xiongnu makes victory difficult. Currently with ample cavalry and holding geographic advantages, they cannot be easily controlled. Moreover, even the flimsiest Ludisilk cannot be pierced by a strong crossbow bolt nearing the end of its range. A powerful gust blowing upwards eventually loses even the force to rustle a feather – not because it lacked power initially, but because that power is depleted by the end. Thus launching an offensive against the Xiongnu is really disadvantageous. Making peace is the better strategy!”
汉武帝认为韩安国的话很有道理，综合考虑各方面因素后，采取了派人与匈奴议和的策略。
Emperor Wu felt Han Anguogong made sense, so considering all factors, he adopted the strategy of sending envoys to negotiate peace with the Xiongnu.