Anyone who is perceived as being accepting of trans individuals will be repetitively asked “what is a woman?”.
The question is rhetorically asked of anyone who includes trans women in their definition of women. It is asked to imply that trans women could not possibly qualify as women, and anyone calling them women must not know what women are.
“What is a woman?” is rarely used to argue that trans men shouldn’t be recognised as men in society. The inverse question “What is a man?” is also rarely asked.
Anti-trans groups, like those who self-identify as gender critical will often use the political slogan “adult human female”, this response is fine on the face of it, but a compact definition of female will elude people making these arguments.
This question is tied to the insistence that in order to advocate for women’s rights, we must have a pat, airtight definition, an assumption that is not born out by other social justice movements, or even previous waves of feminism.
“What is a Woman?” is notably the title of a media production by the self-proclaimed theocratic fascist, Matt Walsh. It has also been used as a “gotcha” question by many media personalities and political pundits as a framing to attack and undermine the acceptance of trans people.