"永不衰老"的英语表达可以是 "ageless"。

这个词的来源可以追溯到古英语 "æg" 或 "ege"，意为 "永恒"，"无限" 或 "无穷"。加上后缀 "-less"，就可以构成 "ageless" 这个形容词，意思是 "永不衰老"。

例句：

The ageless beauty of the mountains never fails to inspire me. (山间永不衰老的美丽总能激发我的灵感。)
The ageless wisdom of the ancient philosophers continues to influence us today. (古代哲学家们永不衰老的智慧继续影响着我们。)
She has an ageless quapty about her that makes her seem timeless. (她有一种永不衰老的特质，使她看起来永远不老。)