The name Marni originates from several languages, including Hebrew, meaning "rejoice", and Latin as a variant of "Marina", meaning "of the sea". It also has derivations from Gaelic and Swahili. "Marni" and "Marnie" are the two most common spellings of the female first name, ranking 2,446 and 1,498, respectively, out of 4,275 for females of all ages in the 1990 U.S. Census. Variants. Due to its many derivations, a number of alternate spellings and related variant names exist, including: Marni. Marnee. Marnie. Marny, a Scandinavian variant of Marina. Marney. Marne. Marna. Marnette. Marnina.
https://en.wikipedia.org/wiki/Marni