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• molly
  molly

  noun

  any of certain livebearing freshwater fishes of the genus Poecilia (formerlyMollienisia ), popular in home aquariums.
• Molly
  Molly

  noun

  a female given name, form of Mary or Milicent.

molly

¹ American  

[mol-ee] / ˈmɒl i /

noun

mollies plural

1. any of certain livebearing freshwater fishes of the genus Poecilia (formerlyMollienisia ), popular in home aquariums.

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molly ² American  

[mol-ee] / ˈmɒl i /

noun

mollies plural

1. a type of expansion bolt having a split, sleevelike sheath threaded at one end so that when inserted snugly into masonry the turning of the bolt draws the ends of the sheath together, thus spreading the sides.

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molly ³ American  

[mol-ee] / ˈmɒl i /

noun

Slang.

1. Often Molly MDMA.

2. any amphetamine.

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molly ⁴ American  

[mol-ee myool] / ˈmɒl i ˌmyul /

noun

1. a female mule.

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Molly ⁵ American  

[mol-ee] / ˈmɒl i /

noun

1. a female given name, form of Mary or Milicent.

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molly ¹ British  

/ ˈmɒlɪ /

noun

1. any brightly coloured tropical or subtropical American freshwater cyprinodont fish of the genus Mollienisia

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molly ² British  

/ ˈmɒlɪ /

noun

1. informal an effeminate, weak, or cowardly boy or man

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Other Word Forms

Inflected Forms

noun

• mollies
  plural

Etymology

Origin of molly¹

First recorded in 1930–35; shortened from New Latin Mollienisia, named after French statesman Count F. N. Mollien (1758–1850); see -ia

Origin of molly²

First recorded in 1930–35; formerly a trademark

Origin of molly³

First recorded in 1975–80; origin uncertain; perhaps a shortening of black molly, a tropical aquarium fish supposedly resembling the black pills; other authorities suggest it is a shortening and alteration of molecule ( def. )

Origin of molly⁴

First recorded in 1980–85; generic use of the proper name

Example Sentences

Court of Federal Claims judge Molly Silfen said tax-filing and payment deadlines were postponed during that time, plus another 60 days, which would have concluded on July 10, 2023.

From MarketWatch • May 27, 2026

A friend reached out to Molly Duane, at the time a senior attorney at the Center for Reproductive Rights, who was representing dozens of women denied medical care under abortion bans.

From Salon • May 27, 2026

Rates Strategist Molly Brooks wrote in a recent note.

From Barron's • May 26, 2026

Andy Burrows, chief executive of Molly Rose Foundation, a UK-based online safety charity, welcomed the report, calling big tech platforms "complacent and evasive when it comes to protecting children from preventable harm".

From BBC • May 21, 2026

Molly didn’t like this, she didn’t like any of it, the way Lena spoke.

From "Night Owls" by A.R. Vishny