Kyūjitai form of 暗号 (“code; cipher”)

dim, faint, dimly lit

a dark cave, a dark underground room

a fragrance or scent from nowhere in particular; often alludes to the scent of plums

(mahjong) concealed kong

(mahjong) to make a concealed kong

absolute darkness / (Buddhism) a complete lack of virtue or wisdom / (color) pure black

(idiomatic) to have grown tense (of a situation); to have become critical (and to be on the verge of a major upheaval)

(mahjong) a 役満 (yakuman, “limit”) hand consisting of four concealed triplets

the darkest place is under the candlestick; can't see the wood for the trees; people often known little of what happens under their noses; lit. "dark under a candlestick"