What is "shibui"

Shibui (渋い) (adjective), shibumi (渋み) (noun), or shibusa (渋さ) (noun) are Japanese words which refer to a particular aesthetic of simple, subtle, and unobtrusive beauty. Like other Japanese aesthetic terms, such as iki and wabi-sabi, shibui can apply to a wide variety of subjects, not just art or fashion.