Feisty describes someone who is lively, determined, and courageous. The word was originally applied to scrappy little hunting dogs. It also, oddly, seems to have something to do with farting. As I used it in my review of The Haunting of Hill House, above: “[The characters] include Dr. Montague, an occult scholar looking for solid evidence of a ‘haunting’; his wife, a believer in spirits; Theodora, a feisty young woman; Luke, the future heir of the house; and Eleanor, a fragile young woman that supposedly had experiences with poltergeists when she was young.”