在英文中，要表达“冷静”的意思，可以使用以下几个常用词语：

calm

Calm 是形容词，意思是“平静的，冷静的”。

例句：

It's important to stay calm in a crisis. (在危机中保持冷静很重要。)
She remained calm even when he raised his voice. (即使他提高了嗓门，她仍然保持冷静。)
cool

Cool 也是形容词，意思是“冷静的，沉着的”。

例句：

He kept his cool under pressure. (他在压力下保持了冷静。)
She's known for her cool head in a crisis. (她因在危机中保持冷静而闻名。)
collected

Collected 是形容词，意思是“冷静的，沉着的”。

例句：

He remained collected even when the situation became chaotic. (即使情况变得混乱，他仍然保持冷静。)
She's always collected under pressure. (她在压力下总是保持冷静。)
composed

Composed 也是形容词，意思是“冷静的，沉着的”。

例句：

He remained composed despite the chaos around him. (即使周围混乱，他仍然保持冷静。)
She always stays composed in stressful situations. (她在紧张的情况下总是保持冷静。)

以上这些形容词的来源都是源自拉丁文，都有“冷静”的意思。在使用时，可以根据具体的上下文和所需的语气来选择适当的词语。