速度快的；迅速的

用法：

作为形容词，speedy用来描述运动或行动的迅速性。它可以作为定语或表语使用。

例句1-5句且中英对照：

1. The cheetah is known for its speedy movements, making it the fastest land animal in the world.（猎豹以其迅速的动作而闻名，使它成为世界上最快的陆地动物。）

2. The delivery service promises to be speedy and efficient, ensuring that your package will arrive on time.（快递服务承诺快速高效，确保您的包裹准时到达。）

3. We need to come up with a speedy solution to this problem before it gets out of hand.（我们需要在问题失控之前想出一个迅速的解决方案。）

4. The new train system has greatly improved transportation in the city, making it much more speedy and convenient for commuters.（新的火车极大地改善了城市交通，在通勤者看来更加快捷方便。）

5. The company's success can be attributed to its speedy decision-making process, allowing them to stay ahead of their compes.（公司的成功归功于其迅速的决策过程，使他们能够领先于竞争对手。）

同义词及用法：

1. Rapid - 形容事物发生或进行得非常快，强调时间紧迫。

例句：The company has experienced rapid growth in the past year.（公司在过去一年经历了快速的增长。）

2. Swift - 形容行动或反应迅速，强调敏捷和灵活。

例句：She made a swift decision and acted on it immediately.（她迅速做出决定并立即采取行动。）

3. Quick - 形容运动或行为迅速，强调速度快。

例句：He has a quick mind and can solve problems efficiently.（他头脑敏捷，能够高效解决问题。）

4. Prompt - 形容行动迅速，强调及时性和效率。

例句：I received a prompt response to my email, which was very helpful.（我收到了对我的电子邮件的及时回复，非常有帮助。）

5. Expedite - 动词，指加快进程或使事情更快地完成。

例句：We need to expedite the process in order to meet the deadline.（为了满足截止日期，我们需要加快进程。）