Marni is a distinctive girls' name in England & Wales, ranking #724 in 1998 with 32 recorded births. The name reached its all-time peak in 2014 with 48 births ranking #802. Since 1996, the popularity has increased by 433.3%. In 1998, approximately 1 in every 9,037 girls born was named Marni. FALLING Recent data shows the name is currently falling.