Misty is from the Old English mist (fog, mist) + the diminutive -y; popularized by Erroll Garner's 1954 jazz standard Misty. Misty Copeland (born 1982) — the first Black female principal dancer in the 75-year history of the American Ballet Theatre (promoted in 2015). Began ballet training at 13 — considered impossibly late — at the Boys & Girls Club in San Pedro, California; joined ABT at 18. Time magazine's 100 Most Influential People (2015). Misty Hyman (born 1979) — surprise 2000 Olympic gold medalist in the 200m butterfly. Misty May-Treanor (born 1977) — three-time Olympic gold medalist in beach volleyball.
Subject of A Ballerina's Tale (2015 documentary) and her memoir Life in Motion (2014).
In Pythagorean numerology the letters of Misty reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.