As a color, 黑 (hēi) means black, and 白 (bái) means white. Both of these words have a number of different meanings and connotations.
白菜 (báicài) is a general term for Chinese cabbage, of which there are several varieties. 大白菜 (dàbáicài) is the large and heavy variety with tightly-wrapped pale leaves. It is also known in the West as Napa cabbage or Chinese lettuce. The pale green and slender loose-leaf type is called 小白菜 (xiǎobáicài white rape). If you are after the smaller variety with crunchy dark-green leaves shaped like Chinese soup spoons, then ask for 青康菜 (Qīng Kāng cài) or 瓢儿菜 (piáor cài). What’s known as “bok choy” has very dark green leaves with sturdy white stalks. Actually, “bok” and “choi” are not Mandarin sounds. “choi” is the Romanization of the Cantonese pronunciation of 菜 (cài vegetables).
白米 (báimǐ) are rice grains from which the husks have been removed. It is the regular white rice sold in grocery stores. 蛋白 (dànbái) are egg whites, and 蛋白质 (dànbáizhì) are proteins. 白血球 (báixiěqiú) are white blood cells.
White is usually associated with cleanliness and purity, as in 洁白 (jiébái spotless). It is also associated with brightness or clarity, as in 白天 (báitiān daytime) or 明白 (míngbai clear, to understand), respectively.
Xiànzài wǒ míngbai le.
Now I understand.
坦白 (tǎnbái) means to be frank and candid.
Tǎnbái shuō, tā bù shìhé zhè zhíwèi.
Frankly, he is not well suited to this position.
白 (bái) also means blank, gratis or in vain.
白痴 (báichī) is an idiot. On the other hand, 白吃 (báichī) means to freeload.
白白 (báibái) means “for nothing”. Do not confuse this with 拜拜 (báibái), which is the Chinese transliteration for “bye-bye”.
Wèile zhèi jiàn shì, wǒ báibái sǔnshī le yī bǎi yuán.
Because of this, I lost one hundred yuan for nothing.
苍白 (cāngbái) means pale or ashen. You could use it to describe gray hair or a wan face.
In contrast, 黑油油 (hēiyōuyōu) means jet-black, or black and shiny. 漆黑 (qīhēi) or 黑漆漆 (hēiqīqī) means pitch-black.
Wàimian hēiqīqī, wǒ bùgǎn chúqu.
It’s pitch-dark out there; I dare not go outside.
黑暗 (hēiàn) means darkness or dark, both in the sense of lacking illumination and in the sense of being shady or evil.
黑心 (hēixīn) is an evil mind. As an adjective, it means being unconscionable. You may have heard news stories about 黑心食品 (hēixīn shípǐn) produced by dishonest manufacturers who have no regard for the consumers’ health. These foods contain cheap non-food-grade ingredients or are tainted with toxic substitutes. One really needs to be careful about what one chooses to ingest.
黑帮 (hēibāng) is a sinister gang, and 黑手党 (hēishǒudǎng) are the Mafia. 黑名单 (hēimíngdān) is a blacklist, and 黑客 (hēikè) is another way of saying computer hackers. When you exchange news about corruption or other wrong-doings in a conversation, you might shake your head and add this remark:
The evil are all the same the world over.
(All ravens in the world are equally black.)
黑白 (hēibái) means black & white, or right and wrong. For example, 黑白照片 (hēibái zhàopiàn) is a black & white photo.
Nǐmen bù kěyǐ hēibáibùfēn.
You should not be without a sense of right and wrong.
清楚 (qīngchǔ) means clear and well-defined, easy to see or understand. Suppose an argument comes up regarding your rented apartment, and you are in the right, show your 房东 (fángdōng landlord or landlady) the rental agreement and say:
Here it is in black and white, and crystal clear.