Why was Sarah vaughan called sassy?

Answer 1

Sarah was given the nickname "Sassy" by pianist John Malachi, who was a member of Billy Eckstine's band when Eckstine invited Sarah to join him in 1944. It was in reference to her down to earth personality, her salty speech (for which she earned another early nickname, "Sailor") and the gregarious style she maintained among friends, although she was seldom so open with those she did not know. Sarah liked the nickname Sassy and it stuck with her throughout her career, both in public and in private, though friends and acquaintances usually shortened it, to "Sass".