I wouldn't know if she was sexy but I always thought Barbra was stunningly knockout beautiful in The Way We Were.
Being sexy is a weird one to define. When I was younger a couple of women in my group were incredibly popular with the men but being blatant they were not particularly pretty (and no it wasn't because they put out.....) they just had a thing about them.
I think that women can't judge a woman's sexiness unless it's seen through their lesbian eyes. Some men find some women sexy. Some women find other women sexy...and so it goes on round the various combinations of gender and sex and aesthetics. But sexiness is really about sweat and smell.
I suspect that women who judge other women as being sexy are simply judging the woman's conformity with what is considered fashionable. I bet none of you women here would be able to predict what I, a man, would find sexy in a woman.
Prudie; quite right. What I find sexy is not necessarily what other humans would find sexy. There's no such thing as the world's sexiest woman. Sexiness is in the hormones of the beholder.
I haven't yet seen every woman ever, so I'm unqualified to judge yet. In any case different characteristics are sexy, so how does one judge one over another ?