A woman or girl, especially of low status.
"The police seized a small baggie containing white molly from the suspect's pocket during the raid."
A fish of the genus Poecilia, except for those known as guppies.
The crystalline or powdered form of MDMA.
In plain English: Molly is slang for ecstasy, which is an illegal drug people sometimes take to feel happy and energetic.
"The molly swam gracefully near the surface of the aquarium tank."
Usage: Molly refers specifically to female mollies within the molly fish family, distinguishing them from male specimens and related species like guppies. In casual conversation about aquariums, this term is often used interchangeably with "female" when discussing these live-bearing freshwater fish.
To engage in (male) homosexual activity with.
"The term "molly" is an archaic slang word that does not carry the definition of engaging in male homosexual activity; instead, historically it referred to a mild form of opium or someone who used such drugs, and modern usage typically refers to a female given name or a type of fish."
In plain English: To molly means to fix something up by adding more of it, usually money or supplies, just enough so that things work again but not perfectly.
"He mollycoddled his child by doing everything for him."
A diminutive of Mary or, less often, Margaret.
"My grandmother affectionately called her granddaughter Molly instead of Mary."
Molly began as an affectionate nickname for the name Mary before taking on other meanings in English. Its modern association with drugs likely stems partly from its use as a pet form and possibly from being linked to the initials of MDMA.