Tranquil 一词逆构自单词 tranquility （平静、宁静、安宁）或者源自拉丁语tranquillus（安静的、平静的、静止的）。15世纪中期出现在英语后，相应也是用来表示“安静的、平静的、安宁的”，常作正式用语使用，主要指一种令人愉快、非常深沉且稳定固有的平静，不受外界混乱干扰或者没有内在思想、精神、情绪上的困扰，

比如：

静谧的景象

a tranquil scene

the tranquil waters of the lake平静无波的湖水

Her tranquil gaze was fixed seawards.她平静地凝望大海。

The world today is far from tranquil. The world economy is under growing downward pressure. Global development is confronted with multiple challenges. That said, we remain unwavering in our belief that the historical trend of peace, development, cooperation and mutual benefit is unstoppable, our people's aspiration for a better life remains strong as ever, and the desire of all countries to achieve common development and prosperity is overwhelming.权威用例当今世界并不太平，世界经济下行压力增大，全球发展面临诸多挑战，但我们坚信，和平、发展、合作、共赢的历史潮流不可阻挡，人民对美好生活的向往不可阻挡，各国实现共同发展繁荣的愿望不可阻挡。

出自习主席在第三届“一带一路”国际合作高峰论坛欢迎宴会上的祝酒辞（双语全文）

serene: calm, peaceful, and untroubled; tranquil placid: (of a person or animal) not easily upset or excited halcyon: denoting a period of time in the past that was idyllically happy and peaceful同近义词