Molly

female proper name, shortened form of Mollie, Molly, itself a familiar of Mary. Used from c. 1600 for "prostitute," but in low slang by early 19c. it also meant "female companion not bound by ties of marriage, but often a life-mate" [Century Dictionary]. It became a general word for "woman" in old underworld slang, for instance Moll-buzzer "pickpocket who specializes in women;" Moll-tooler "female pick-pocket." U.S. sense of "a gangster's girlfriend" is by 1923.

fem. proper name, Old English Maria, Marie, name of the mother of Jesus, from Latin Maria, from Greek Mariam, Maria, from Aramaic Maryam, from Hebrew Miryam, name of the sister of Moses (Exodus xv), a word of unknown origin, said to mean literally "rebellion."

The nursery rhyme "Mary had a Little Lamb" was written early 1830 by Sarah Josepha Hale of Boston and published September 1830 in "Juvenile Miscellany," a popular magazine for children. Mary Jane is 1921 as the proprietary name of a kind of low-heeled shoe worn chiefly by young girls, 1928 as slang for marijuana. Mary Sue as a type of fictional character is attested by 1999, from the name of a character in the 1973 parody story A Trekkie's Tale.

also molly-coddle, by 1839 (implied in mollycoddling), from a noun (by 1828) meaning "overly pampered, fastidious, effeminate male," from Molly (pet name formation from Mary), which had been used contemptuously at least since 1707 for "a milksop, an effeminate man" (see molly (n.1)) + coddle (q.v.). Related: Mollycoddled.

All his pursuits had been sedentary; for he never went out but with his mother. He was not allowed to stroll about the farm with his father, lest he should get his clothes dirty and his feet wet. In short, he was what Giles Darman pronounced him to be—"a little mollycoddle." ["Babbington Droneham," Hood's Magazine, March 1844]