So, I was under the impression that "frenemies" came from Sex in the City. I don't know why I was under that impression, but there it is...
Actually the word "frenemy" was first used in print in 1977 by Jessica Mitford in a piece she did for The Daily Mail:
Actually, I soon discovered that a substantial number of the names listed in my address book belong in the category of Frenemy, an incredibly useful word that should be in every dictionary, coined by one of my sisters when she was a small child to describe a rather dull little girl who lived near us. My sister and the Frenemy played together constantly, invited each other to tea at least once a week, were inseparable companions, all the time disliking each other heartily.
I wonder whether most of us do not, in fact, spend more time with frenemies than with actual friends or outright enemies? Those fringy folks whose proximity, either territorial or work-related, demands the frequent dinner invitation and acceptance of their return hospitality? Pondering the potential guest list, dear reader, how often have you and your spouse bickered on in this fashion: “Well, if we ask Geraldine, we’ll have to ask Mary and her awful boy-friend.” “We can’t just ask Peter from my office and not the others—makes for bad blood. If we ask Peter, we’ve got to have the lot.”
Read the whole piece at A Different Stripe