The name Marnie is a girl's name of Hebrew origin meaning "rejoice". Marnie and is often added to lists like Hipster British Baby Names for Girls and discussed in our forums with posts like "Girls Makeover - Two Middles".
From the experts:
Short form that's much better known than the original, now dated to the era of the Hitchcock movie that made it famous. This may change since it was recently chosen by British singer Lily Allen, whose first daughter was christened the retro Ethel and is also attached to one of the more attractive characters on the tv show Girls.