When I started to learn Mandarin nearly half a century ago, it used to be that xiǎojiě 小姐 ("miss") was a polite way to refer to or address a young, unmarried woman. You could also extend xiǎojiě 小姐 ("miss", lit., "little elder sister") to convey other, related meanings, such as lǎo xiǎojiě 老小姐 ("old maid / miss"), xiǎojiě píqì 小姐脾气 ("petulant; flirtatious; coquettish"), and so forth. Gradually, however, xiǎojiě 小姐 ("miss") evolved to the point that it often came to be used in a jocular or facetious manner. Furthermore, when used by itself, xiǎojiě 小姐 may be applied to prostitutes, so one must be careful when referring to someone with this word. It seems that there is no longer a broadly accepted, relatively respectful term of address for a young, single woman.
Preceded by a surname, xiǎojiě 小姐 ("miss") is still an acceptable appellation. For example, Zhāng xiǎojiě 张小姐 ("Miss Zhang"), Li xiǎojiě 李小姐 ("Miss Li"), Wáng xiǎojiě 王小姐 ("Miss Wang"). Huānyíng gèwèi cānjiā Li Míng xiānshēng yǔ Zhāng Hóng xiǎojiě de hūnlǐ 欢迎各位参加李明先生与张红小姐的婚礼 ("You are all welcome to attend the wedding of Mr. Li Ming and Miss Zhang Hong").
Another term that was used to refer to a young, unmarried woman is gūniang 姑娘 ("girl"), but nowadays it is employed chiefly by elders. A derived term is xiǎo gūniang 小姑娘 ("young / little girl"). Gūniang 姑娘 ("girl") may still be used as a polite term of address: Gūniang, qǐngwèn Běijīng dàxué zěnme zǒu? 姑娘, 请问北京大学怎么走? ("Young lady, how can I get to Peking University?").
Sometimes when one wishes to flatter a woman for her comely appearance, one may call her a měinǚ 美女 ("beauty"), but that obviously is not suitable for common use, since not every young woman is pretty, and its overuse might readily be construed as satirical. Furthermore, měinǚ 美女 ("beauty") may also be used to refer to a married woman. In most cases it would not be appropriate to walk up to someone on the street and say, "Měinǚ, qǐngwèn Qīnghuá dàxué zěnme zǒu?" 美女, 请问清华大学怎么走？("Beauty, how can I get to Tsinghua University?"), although a proper woman might occasionally address a pretty young lady this way and, as one of my informants put it, "a decent young man" might also do so without sounding lecherous.
An affectionate appellation is niū 妞 ("little girl; lass"), but it has only restricted application.
There are numerous terms of address that are formed by prefixing nǚ 女 ("female") to words that were traditionally restricted to males, e.g., nǚláng 女郎 ("girl", lit., "female youth; female young gentleman"), as used in the expression shíshàng nǚláng 时尚女郎 ("fashionable girl")
Another such term is nǚshēng 女生 ("girl", lit., "female student" [students in traditional society were almost always male, except in the rare instances when girls masqueraded as boys so as to gain an education]). This Taiwanese expression, nǚshēng 女生, is becoming increasingly popular on the mainland, even for women who are long past graduation.
In China, it is very hard to tell whether a young lady is married or not. Consequently, nǚshì 女士 (lit., "female scholar / knight / warrior / gentleman") has become quite popular in the sense of "Ms." and can be used for both married and unmarried women. In appropriate circumstances, it may also be rendered by "lady" or "madam".
A once pejorative term, but now not as negative as before, shèngnǚ 剩女 (lit., "leftover woman"), is widely used for single and unmarried females of the age around 30 or over. Even those women who are referred to as shèngnǚ 剩女 (lit., "leftover woman") themselves tend to accept such an appellation since, for whatever reason, it is a fact that they remain unmarried and are unable to change the situation. Shèngnǚ 剩女 (lit., "leftover woman") is somewhat comparable to guānggùn 光棍 ("bachelor", lit., "bare branch") for males, for which see "The transcription of the name 'China' in Chinese characters" and the extensive comments thereto.
In contrast, a fair-complexioned, rich, and pretty single female in her twenties or thirties is extolled as báifùměi 白富美 (lit., "white[not ethnically]-wealthy-beautiful"). Generally such females are highly esteemed by the multitude and are avidly sought after by their male counterparts, who are said to be gāofùshuài 高富帅 (lit., "tall-wealthy-handsome").
In web language today, netizens rarely use plain, ordinary words like xiǎojiě 小姐 ("miss") and gūniang 姑娘 ("girl"). Instead, aside from fancy expressions like báifùměi 白富美 ("white-wealthy-beautiful") and gāofùshuài 高富帅 ("tall-wealthy-handsome"), which have been discussed in the previous paragraph, they have introduced sexually-derived words such as diǎosī 屌丝 (the surface signification of the constituent characters is "cock / prick threads"; also written as diàosī 吊丝 [lit., "hanging threads"]) and hēi mù'ěr 黑木耳 (lit., "black wood ear" [Auricularia auricula-judae]).
For a discussion of the origins and meaning of diǎosī 屌丝, see here and here (both in Chinese). I think that the best translation of diǎosī 屌丝 is "loser", as in Beck's famous lament, "I'm a loser, baby, so why don't you kill me", but it has also been rendered as "creep, nerd, dick, jerk, sucker", and so forth.
As for why hēi mù'ěr 黑木耳 ("black wood ear" [Auricularia auricula-judae]) was chosen to represent the object of diǎosī 屌丝 ("loser") lust, one need only look at pictures of this fungus to understand why lewd young men are obsessed with it as an emblem of erotic fantasy. In essence, hēi mù'ěr 黑木耳 ("black wood ear" [Auricularia auricula-judae]) stands for unmarried females with copious experience of sexual activity. The odd English term for this fungus, "Jew's ear", has been discussed on Language Log here, especially in the comments.
But hēi mù'ěr 黑木耳 ("black wood ear") is only one of countless unflattering terms for women. The artist and designer, Zhang Ting 张婷, has made a short video that provides clever enactments illustrating 26 uncomplimentary words for women. She has provided her own English translations of the Chinese terms (occasionally I add a note of explanation or amplification in square brackets):
1. jī 鸡 (prostitute, lit., "chicken")
2. huángmǐ 黄米 (secret prostitute, lit., "yellow rice")
3. yuànfù 怨妇 (bitter woman)
4. èrnǎi 二奶 (trophy mistress, lit., "two boobs")
5. biǎozi 婊子 (whore)
6. dàngfù 荡妇 (jade [, slut], lit., "swinging woman")
7. pōfù 泼妇 (shrew [, vixen, virago, scold, catamaran], lit., "pouring woman")
8. huāpíng 花瓶 ([flower] vase)
9. lànghuò 浪货 (trollop, lit., "waving goods [/wares])
10. mǎzi 马子 (girlfriend [; toilet], lit., "horse")
11. pòxié 破鞋 (loose woman, lit., "broken shoe")
12. yínwá 淫娃 (lascivious child)
13. jiànbī 贱逼 (cheap cunt)
14. huòshuǐ 祸水 (femme fatale, lit., "baneful water")
15. bāpó 八婆 (nosy woman [; bitch], lit., "eight old woman")
16. lǎo chǔnǚ 老处女 (old virgin [; spinster])
17. sāo niángmen 骚娘们 (lewd woman [; bitch], lit., "stinking woman")
18. nánrén pó 男人婆 (manly old woman [; tomboy])
19. è póniáng 恶婆娘 (ferocious old woman)
20. chángshéfù 长舌妇 (yenta [; gossip, bigmouth, loquacious woman], lit., "long-tongued woman")
21. húlíjīng 狐狸精 (seductress, lit., "fox spirit")
22. shísān diǎn 十三点 (insane woman, lit., "thirteen dots")
23. sǐ sānbā 死三八 (damned bitch, lit., "dead three eight")
24. mǔ yèchā 母夜叉 (female yaksha [/demon; dominatrix])
25. gōnggòng qìchē 公共汽车 (slut, lit., "public bus")
26. tàipíng gōngzhǔ 太平公主 (Princess Too Flat)
To sum up the vocabulary for unmarried young women, shèngnǚ 剩女 ("leftover woman"), báifùměi 白富美 ("white-wealthy-beautiful"), and hēi mù'ěr 黑木耳 ("black wood ear") are currently widely used to refer to single, unmarried females, especially in slang or on the web. Xiǎojiě 小姐 ("miss"), gūniang 姑娘 ("girl"), měinǚ 美女 ("beauty"), and nǚshì 女士 ("Ms.") are still used more formally, but not as commonly as in the past.
Not only is the vocabulary pertaining to women (especially those who are unmarried) derogatory, it has long been recognized that the Chinese character system is biased against women, with many disparaging terms being written with characters containing the female semantic classifier (Kangxi radical no. 38). Here are just a few of the many that could be listed:
1. nú 奴 ("slave; servant; despicable yes-man")
2. jiān 奸 ("false; selfish; disloyal; crafty; wicked; evil; treacherous; villainous; cunning; traitor; illicit sexual relations; adultery; fornication; licentiousness")
3. wàng 妄 ("absurd; untrue; false; ignorant; stupid; wild; rash; fanciful; fantastical; reckless; presumptuous; preposterous")
4. dù 妒 ("jealous; envy")
5. jiān 姦 ("adultery; debauch; ravish; a crook")
6. jí 嫉 ("jealousy; envy; hate; detest")
7. yāo 妖 ("monster; demon; devil; witch; goblin; phantom; weird; unaccountable")
There are a few characters containing the graph for female that have a positive connotation (e.g., hǎo 好 ["good" — composed of "woman and child"] and ān 安 ("safe; secure; peaceful; quiet; calm; content" — made up of a woman beneath a roof), but the overwhelming majority of characters containing the female semantic classifier and indicating negative or positive qualities are clearly on the negative end of the scale. Naturally, most characters having the female semantic classifier simply describe feminine qualities (winsomeness, beauty, agreeableness, and so forth) or female status and position (wife, sister, concubine, etc.).
David Moser has written a detailed study of other types of negative linguistic stereotyping of women in Chinese. See his "Covert Sexism in Mandarin Chinese", Sino-Platonic Papers, 74 (January, 1997).
It would appear that terms for women, especially single ladies, are in a state of rapid transition. This is probably a reflection of what is happening in society as a whole, where social roles and social status are highly unstable. As is true of so many other aspects of contemporary life, the internet — with its constantly fluctuating fashions — is one of the main driving forces behind these changes in terminology.
[A tip of the hat to Arthur Waldron and thanks to Gianni Wan, Jing Wen, Jeremy Goldkorn, Eric Mu, Denis Mair, and Rebecca Fu. This post is dedicated to M. R., who is fond of single ladies, especially his friend Katherine.]