astringent; bitter; puckery; rough; harsh; tart
austere; elegant (and unobtrusive); refined; quiet (and simple); sober; sombre; subdued; tasteful (in a quiet way); understated
sour (look); glum; grim; sullen; sulky
stingy; tight-fisted
渋い顔をして黙っていた。
He was silent with a bitter expression.
この茶は渋くて飲みにくい。
This tea is astringent and hard to drink.
祖父は渋かった表情を崩して笑った。
My grandfather broke his stern expression and smiled.