Mono no aware (物の哀れ) - Literally "the pathos of things", and also translated as "an empathy toward things", or "a sensitivity to ephemera", is a Japanese term for the awareness of impermanence (無常 mujō), or transience of things, and both a transient gentle sadness (or wistfulness) at their passing as well as a longer, deeper gentle sadness about this state being the reality of life.
Source- Wikipedia, yes the Wikipedia that is my source, do you have a problem with that? This is 2018 ok, they don’t print the encyclopedia anymore, get over it.
Metaphors for life on earth
What is a man’s life but a fleeting dream, a passing shadow, a vaporous cloud, a gust of wind, and a swirl of dust?- Rosh Ha Shannah Liturgy
(12) Who can possibly know what is best for a man to do in life—the few days of his fleeting life? they are made like a shadow For who can tell him what the future holds for him under the sun?