Swithin \s-within, swi-thin\ as a boy's name is of Old English origin, and the meaning of Swithin is "quick, strong". Saint Swithin was a ninth-century bishop of winchester in England. It was said that whatever the weather was like on his feast day on July 15, it would remain the same for the next forty days.
Swithin has 2 variant forms: Swithinn and Swithun.
Baby names that sound like Swithin are Chetwin, Chetwyn and Chetwen.
Swithin is not a popular first name for men and an equally uncommon surname or last name for both men and women. (1990 U.S. Census)