Which is the proper adjective?
'Female' as a Noun
Now on the flip side, Liz from Austin, Texas, called in to say her pet peeve is when people refer to women as females—for example, when someone says, “I was chatting to some females.” To her, that sounds very scientific and awkward.
Merriam-Webster's Dictionary of English Usage notes that esteemed authors in the 1800s used female in this way. And those authors were women.
Jane Austen used the phrase "the females of the family" in Pride and Prejudice, for example, and Emily Brontë wrote "It opened into the house, where the females were already astir" in Wuthering Heights.
Yet even back in those times other people complained that using female in this way was demeaning (5), and I agree with Liz that it doesn't sound right today. Merriam-Webster's goes on to say that the neutral use of Austen and Brontë has faded away, and the most common use of the word female now as a noun is to refer to lower animals. For example, if you were studying apes, you could say something like, “The females formed a small group to defend against the attackers.” (6)
It's my recommendation that you use female as a noun only when you are speaking about animals or writing scientifically. When you are talking about female humans, the favored nouns are woman and women. Likewise, when you're talking about male humans, the favored nouns are man and men.
1. woman. Merriam-Webster Online Dictionary. http://www.merriam-webster.com/dictionary/woman (accessed June 8, 2016).
2. woman. The American Heritage® Dictionary of the English Language, Fifth Edition. Houghton Mifflin Harcourt Publishing Company, 2015. https://ahdictionary.com/word/search.html?q=woman&submit.x=0&submit.y=0 (accessed June 8, 2016).
3. woman. Dictionary.com. Dictionary.com Unabridged (v 1.1). Random House, Inc. http://dictionary.reference.com/browse/woman (accessed June 8, 2016).
4. woman. Oxford English Dictionary. Second edition. Oxford University Press, http://0-www.oed.com.innopac.library.unr.edu/view/Entry/229884?rskey=zgmG44&result=1#eid (accessed June 8, 2016, subscription required).
5. Merriam-Webster's Dictionary of English Usage. Springfield: Merriam-Webster, 1994, pp. 440-41.
6. American Heritage Guide to Contemporary Usage and Style. Boston: Houghton Mifflin Company, 2005, pp. 180-81.