antiestrogen

noun

an·​ti·​es·​tro·​gen ˌan-tē-ˈe-strə-jən How to pronounce antiestrogen (audio)
ˌan-tī-
British -ˈē-
variants or British antioestrogen
: a substance (such as tamoxifen) that inhibits the physiological action of an estrogen
… acts like an antiestrogen in breast and uterine tissue, thus protecting against hormone-stimulated cancers …Jane E. Brody
antiestrogenic adjective
or British antioestrogenic
antiestrogenic agents
an antiestrogenic effect

Word History

First Known Use

1965, in the meaning defined above

Time Traveler
The first known use of antiestrogen was in 1965

Cite this Entry

“Antiestrogen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antiestrogen. Accessed 28 Jul. 2026.

Medical Definition

antiestrogen

noun
an·​ti·​es·​tro·​gen
: a substance (as tamoxifen) that inhibits the physiological action of an estrogen
antiestrogenic adjective
antiestrogenic agents
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