迥然不同 vastly different
Explanation
形容事物差别很大，完全不同。
Describes a great difference between things, completely different.
Origin Story
话说唐朝时期，扬州城里住着两位才子，一位是擅长诗词歌赋的李白，一位是精通音律的张九龄。两人虽同为文人，但性情迥然不同。李白豪放不羁，诗作气势磅礴，常饮酒作乐，放浪形骸；而张九龄则沉稳内敛，诗风清丽脱俗，为人正直，勤政爱民。一日，两人同游瘦西湖，李白兴致勃勃地挥毫泼墨，写下了一首豪迈的诗篇，赞叹西湖的壮阔秀丽；张九龄则静静地欣赏着湖光山色，并用他那独特的音律创作了一曲悠扬的乐章，抒发了对自然的热爱。两人各自展现出不同的才情与魅力，虽都以文为业，却如同天上的明月与地上的流水，迥然不同，却又相映生辉。
In the Tang Dynasty, there lived in Yangzhou city two talented men: one was Li Bai, renowned for his poetry; the other was Zhang Jiuling, skilled in music. Though both were men of letters, their temperaments were vastly different. Li Bai was unrestrained and bold, his poems grand and imposing; he often drank and was carefree. Zhang Jiuling was calm and reserved, his poetry elegant and refined. He was honest, diligent, and loved the people. One day, they visited the scenic Slender West Lake. Li Bai joyfully seized his brush and painted a majestic poem praising the grandeur and beauty of the lake. Zhang Jiuling quietly took in the scenery and composed a peaceful piece of music expressing his love of nature. Each showcased their unique talent and charm; while both men were scholars, they were as distinct as the moon in the sky and the flowing water on the earth, vastly different yet complementing each other.
Usage
用于形容两者之间差异巨大，完全不同。
Used to describe the huge difference between two things, completely different.
Examples
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这两个方案迥然不同，需要仔细权衡利弊。
zhè liǎng gè fāng'àn jiǒng rán bù tóng, xūyào zǐxì quán héng lìbì
These two plans are vastly different and require careful consideration of the pros and cons.
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他的想法和我们的迥然不同，难以达成共识。
tā de xiǎngfǎ hé wǒmen de jiǒng rán bù tóng, nán yǐ dá chéng gòngshì
His ideas are vastly different from ours, making it difficult to reach a consensus.
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现代建筑和古代建筑迥然不同，风格各异。
xiàndài jiànzhù hé gǔdài jiànzhù jiǒng rán bù tóng, fēnggé gèyì
Modern architecture is vastly different from ancient architecture, with distinct styles.