The extremity of something is its furthest end or edge.
例句
...a small port on the north-western extremity of the Iberian peninsula.伊比利亚半岛西北端的小港口...the extremities of the aeroplane.飞机的末端
N-PLURAL
（身体的）末端，末梢;（尤指）手脚
Your extremities are the end parts of your body, especially your hands and feet.
例句
He found that his extremities grew cold...他发现手脚变冷了。Exercise is very important as it keeps the circulation moving and warms the extremities.锻炼非常重要，它可以促进血液循环，保持手脚温暖。
N-UNCOUNT
极度;极端
The extremity of a situation or of someone's behaviour is the degree to which it is severe, unusual, or unacceptable.
例句
In spite of the extremity of her seclusion she was sane...尽管完全与世隔绝，她依然心智健全。In the past, the region had been protected by its forbidding geography and the extremities of its climate...过去，这个地区令人生畏的地理条件和极端的天气状况使它受到保护。