What does Kassidy mean, popularity, numerology and more. The name Kassidy is of Irish origin. The meaning of Kassidy is clever. It is also of English origin, where its meaning is curly headed.t ranked 6803 in popular baby names for boys with 12 occurrences. View the Kassidy Name Popularity Page to see how the popularity trend for Kassidy has changed since 1880, or to compare the popularity of Kassidy to other names. Kassidy is a variant spelling of Cassidy.