eonism

Meanings

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.