しぶとい

しぶとい · shibutoi · JLPT N1 · noun

stubborn

🐂 shibu = astringent, tough like unripe persimmon; 'shibutoi' = tough-as-persimmon-skin holdout

Shibui means astringent, and shibutoi is the sticky, tough tenacity of someone who won't let go. Think of a stubborn bull that refuses to be moved.