渋 (Kanji for bitter flavor)

bitter - Well, not just REGULAR bitter (which is 苦い　（にがい）), but a really specific KIND of bitterness that only Japanese people can taste!

In fact, my Japanese friends could only think of 3 cases where you'd use it: unripe fruit, too-strong green tea, or certain raw persimmons.

Shibui can also refer to a sort of sophisticated, cooly sexy older man, such as George Clooney or Keifer Sutherland.

What the hell IS it with this word??

Onyomi

JUU	Mention JEWs to an Iranian and they make a bitter face like :

This tastes so bitter I have to stop and drink some sparkling water to wash out the taste

しぶ*い	bitter 1/2 KANA ★★★☆☆

渋滞(じゅうたい)

traffic jam ★★★☆☆
渋 (bitter flavor) + 滞 (delay / be overdue) = 渋滞 (traffic jam)

渋谷(しぶや)

Shibuya ★★★☆☆
渋 (bitter flavor) + 谷 (valley) = 渋谷 (Shibuya)

the Shibuya neighborhood of Tokyo (lit. 'bitter valley'、which kind of makes sense when you go there and smell it.)