Cletis is of Greek origin, derived from the name Kleitos, which means "glorious" or "famous." It was popularized by the ancient Greek historian Xenophon, who wrote about a character named Kleitos the Black in his work Anabasis. In English-speaking countries, Cletis gained some popularity in the mid-20th century but has since become less common. The name Cletis is often associated with uniqueness and rarity due to its infrequent usage today. It is typically used for boys.
"Cletis experienced peaks in popularity during the early 1920s and again in the late 1920s to early 1930s, with notable years being 1920, 1925, 1927, and 1931. However, it was relatively uncommon throughout most of the century, as suggested by the low totals in other years."