# eonism

> English word · Noun · IPA /ˈi.əˌnɪzəm/

## Definitions
1. The pretence of being the opposite sex, especially that by a man of being a woman; transvestism.

## Etymology
Coined in 1920 by the British physician and sexologist Havelock Ellis (1859–1939) after Chevalier d'Eon (1728–1810), a French diplomat, spy and soldier who presented as male for 49 years, then as a female for 33. Ellis had previously used the term sexo-aesthetic inversion.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/eonism