Why did he....
keep calling her "Minx"? Did I miss something?
shareI believe in his early letters to his brother before he fell in love with her, he referred to her as a "minx".
I think she's the saddest girl ever to hold a martini.
This was a real nickname Keats had for Fanny because of her flirtatious ways. That was one of the qualities that apparently made Keats quite jealous and suspicious of Fanny when they were apart, and can be seen in some of the love letters he wrote to her which were highly emotional and jealous in tone.
This website provides really good insight into their relationship:
http://englishhistory.net/keats/fannybrawne.html