Woman
𐑢𐑫𐑥𐑩𐑯
"Define 'woman'" is a rhetorical question routinely asked by transphobes, as an attempted gotcha against trans women. (They never seem to demand anyone "define 'man'".) As an autist, I've never been good at spotting rhetorical questions, and have generally been much better at reading far too much theory and pondering things far too deeply. So here's my answer.
As far as I can tell, a woman is an adult human whose gender orientation is female. That is to say, an adult human whose brain needs her body to be female in order to be happy and comfortable. Usually the gender orientation aspect goes unnoticed, in favour of the simplistic assumption that a woman is an adult human whose body is already female. This is because most people, including most women, are both cis and endosex.
However, occasionally someone's sex can be quite nebulous, and so any attempt to definitevely categorise it is doomed to failure. Specifically, your chromosomal, genital, gonadal, neurological, hormonal, and legal sex may not necessarily all align, as is the case with intersex and trans people.
Personally, I believe in consent and bodily autonomy. I certainly wouldn't want to deny anyone their womanhood, manhood, or nonbinaryhood. You know who you are better than a complete stranger does — doubly so a bigot — even if you don't yet have the terminology for it.
Debunking authoritarian talking points: Dysmorphia and dysphoria | Woman
Gender and sex: Dysmorphia and dysphoria | Gender dysphoria | Gender orientation | Medical model | Woman