In the context of the book, the term is used to describe the character of Lady Clarice "Clarrie" Fitz-Warrender, who is initially described as being "a woman of dazzling beauty and a personality that could make a grown man turn tail and run." She is a captivating and alluring presence, but she also possesses a sharp wit and a tendency to manipulate people to get what she wants. This combination of beauty and danger makes her a "panther woman" in the eyes of the characters in the story.
The description of Lady Clarice as a "panther woman" is meant to be both flattering and slightly menacing. It highlights her attractiveness and her ability to charm and beguile, but it also suggests that she is capable of causing trouble and that her intentions are not always clear.
The term "panther woman" is a bit of a cliché, but Wodehouse uses it effectively to create a vivid and memorable character. Lady Clarrie is one of the most popular characters in the book, and her "panther-like" qualities contribute significantly to her appeal.