Wabi-sabi (侘寂?) represents a comprehensive Japanese world view or aesthetic centered on the acceptance of transience and imperfection. The aesthetic is sometimes described as one of beauty that is "imperfect, impermanent, and incomplete". It is a concept derived from the Buddhist teaching of the three marks of existence (三法印 sanbōin?), specifically impermanence (無常 mujō?), the other two being suffering (苦 ku?) and emptiness or absence of self-nature (空 kū?).
Here's an interesting explanation that I got from a Pinterest post: