evanescent

This word captures a sense of fragile, fleeting beauty. It is far more poetic and delicate than "temporary" or "short-lived," often evoking an image of mist, smoke, or a dying light. It suggests a process of gradual dissolution rather than a sudden stop.

In a psychological or emotional context, it describes feelings that are barely graspable, like a half-remembered dream or a passing whim. It carries a tinge of melancholy, emphasizing the inevitability of loss and the transient nature of existence.