I would be satisfied to get a definition of "woman" that works in any situation, but that is not a circular definition. I've never gotten anything other than "adult human female", or some slight variation of "anyone who identifies as a woman".
A couple thread iterations ago we looked at the definition issue in general. In short:
By Munchhausen's trilemma we have 3 options for defining "woman":
1. Circular. This is to be rejected as meaningless.
2. Infinite regress. To be rejected as well.
3. Axiomatic. Defining "woman" in terms of more fundamental terms, let's go with this. We have 2 more fundamental notions to use, sex (biological) or gender (sociological). Giving us:
3a: Defining "woman" as a female (sex) person. this is the mainstream and dictionary definition.
3b: Defining "woman" as a feminine (gender) person.
From 3a it follows that transwomen are not women. From 3b it follows that anyone not feminine is not a woman. For example the following follows:
3a1: Butch lesbians aren't women.
3a2: Women must have long hair.
3a3: Women must be submissive.
etc
So it's not just that a definition for "woman" hasn't been provided but that one can not exist that doesn't immediately lead to the regressive statements under 3a and similar.
From this we can also conclude that people like Boudicca who claim to have super-secret special definitions of "woman" that make their claims work are mistaken, as such definitions can not exist. Not just are unknown to exist, but
can not exist.