mifepristone

American

[mif-uh-pris-tohn] / ˌmɪf əˈprɪs toʊn /

noun

an antigestational drug, C 29 H 35 NO 2 , that prevents a fertilized egg from attaching to the uterine wall by blocking the action of progesterone.

mifepristone British

/ mɪˈfɛprɪˌstəʊn /

noun

an antiprogestogenic steroid, used in the medical termination of pregnancy. Formula: C 29 H 35 NO 2

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of mifepristone

1985–90; probably alteration of (a)mi(no)phe(nol) + pr(opyl) + est(radiol) + -one

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

While misoprostol, which is commonly prescribed for ulcer prevention, can be used alone for abortions, it is less effective and less safe than when it’s used in combination with mifepristone.

From Salon • Feb. 9, 2026

Corcept has one marketed product, called Korlym, which is a presentation of the drug mifepristone used to control hyperglycemia in certain patients with Cushing syndrome.

From Barron's • Dec. 31, 2025

The FDA also approved a generic version of mifepristone in 2019.

From The Wall Street Journal • Oct. 2, 2025

RFK referenced a recent study by the Ethics and Public Policy Center, a socially conservative think tank, that released what it claimed was the largest-ever study of mifepristone.

From Slate • May 20, 2025

In 2000, the FDA approved the use of mifepristone as safe and effective for ending an early pregnancy.

From Los Angeles Times • Jun. 13, 2024

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023