These characters combine in a very direct and literal way: 长生 (chángshēng) means “long life,” and 不老 (bùlǎo) means “not old.” Put together, `长生不老` means “to have a long life and not get old”—immortality with eternal youth.
`长生不老` is far more than just a phrase; it's a window into the Chinese cultural psyche regarding life, death, and time. Its roots are deeply entwined with Taoism (道教 - Dàojiào), a philosophy and religion where one of the ultimate goals is to achieve harmony with the Tao and, for some practitioners, to become a 仙 (xiān)—an immortal, transcendent being. This wasn't a passive state but was actively pursued through alchemy (seeking an elixir of life, or 仙丹 - xiāndān), specific breathing exercises, meditation, and diets. The most famous historical example is Qin Shi Huang (秦始皇), the first emperor of a unified China. He was famously obsessed with achieving immortality, sending vast expeditions in search of the mythical elixir of `长生不老`. This historical quest has cemented the phrase in the collective memory of Chinese culture. Compared to the Western concept of “immortality,” `长生不老` is more specific. Western immortality (e.g., a Greek god or a vampire) often just means “cannot die.” One could be eternally old, eternally wounded, or eternally miserable. `长生不老`, however, explicitly includes the “never aging” clause, making it a concept more similar to the Western quest for the Fountain of Youth. It's about preserving life at its peak, not just extending it indefinitely.
While no one uses this term literally in everyday life, it is extremely common in specific contexts.