I’ve read this expression scores of times, but it’s not something anyone I’ve ever met has actually said. Clearly it’s a cutting remark, but I’m not sure I understand it fully. Where does the “ought” come into it when it seems to suggest she’s not a better person than you’d expect? Does it mean her family is low-class and you can’t expect better of those people? Or is it more to suggest that as one can predict, she in particular hasn’t made anything of herself (or shouldn’t even try to)? Or… what?
It can be used in both senses. Usually it connotes promiscuity.
It’s not just confined to class, since you can substitute ethnic heritage or religion or place of birth or whatever other differences people use to demean one another.
If the woman is the same class or whatever as you, then it probably means that she could - and should - have been as wonderful and virtuous as you and your family are but she chose not to be because her moral character isn’t as good as yours.
The phrasing is just old-fashioned to modern ears. I don’t think that you should read anything extra into “ought.”
Speaking of old-fashioned: What, exactly, is an ‘old-fashioned look’? I think I get what the phrase means (what I might call ‘the evil eye’) but why is it old-fashioned?
Wouldn’t an old-fashioned look be an appearance? Not a look as in the way you look at somebody, but referring to the dress/style which harkens back to a previous era.
You’d think, but no: Terry Pratchett explicitly refers to an ‘old-fashioned look’ in many of his novels in a way that completely excludes that interpretation, using sentences like “She shot him a very old-fashioned look.”
My interpretation is that the expression means “She’s no better than she needs to be [to remain within the prevailing standards of public decency and virtue]” – i.e. while they have no evidence, as such, they strongly suspect her of enjoying herself in private – or at the very least thinking about it.
I also puzzled over this for years, then I was thinking about someone’s behavior…and bing…suddenly there was a perfect match: The phrase came unbidden to mind.
It’s not class related, but about morality. It’s someone who is morally or spiritually lazy. They’re honest, their behavior isn’t open to criticism, but they aren’t trying to better themselves. There are things they easily could have done that they didn’t. People they could have helped if they had more genuine, practical concern about others.
In terms of a “spiritual voyage”, it’s someone who is complacent. Not the sort of person you’d associate with uplifting “random acts of kindness”. Stuck. Bob Dylan’s line: “Those who are not busy being born are busy dying.” So it’s not a nice thing to say about someone: that they’re morally, spiritually moribund.
Rather like the word “ordinary” in modern slang. Strictly speaking it ought to mean “average, unremarkable” but in fact the way people use it it generally means something particularly bad. “That meal was pretty ordinary” = “well at least it didn’t give me food poisoning, that’s about all that can be said for it”
The phrase seems to be open to several interpretations. I was raised in Lancashire, in the north-west of England. I’ve heard the expression used in a forgiving and tolerant way that could be paraphrased as, ‘This person may not be all that impressive (limited achievements, limited personal appeal) etc., but given his background, family, circumstances and so on, it’s understandable that he has turned out the way he has, and at least he doesn’t pretend to be anything that he isn’t’.
I came across this phrase in the blurb on the back cover of an “Inspector Morse” paperback, and was mystified. Working from memory here, it referred to a murder victim as a “divorcée, no better than she ought to be”.
It was clearly an established phrase or formula, with an established meaning.
The context, and the book itself, support a reading of the phrase as “sexually loose”, which is quite different to most of the interpretations suggested in this thread.
(except the very first one suggested, which I somehow managed to overlook. Sorry Exapno!)
Margaret Mitchell uses this term in Gone With the Wind. IIRC, Grandma Fontaine was talking to Scarlett about the girls her grandsons liked to fool around with.
There were two types of women…those you married, and those you didn’t.
Actually my take on it has always been that the speaker is somewhat charmed and a little bit in awe, as of a wild one who gets what she wants (including as much pleasure as she wants). Someone who’s not malicious, who walks lightly on the earth and doesn’t bother much about other folks’ hangups.
But what do I know?
I think it means “a vaguely disapproving or puzzled look, as might be pictured as coming from an old-fashioned librarian or nun”
… you say in the very old-fashioned thread. 
Thanks for responding, though; I’d given up on that question.
Interesting. I suppose finding out where it came from is out of the question.
Hope I’m not quoting too much for SDMB’s fair use:
Biggles No, no, no, you loopy brothel inmate.
Secretary I’ve had enough of this. I am not a courtesan. (moves round to front of the desk, sits on it and crosses her legs provocatively)
Biggles Oh, oh, ‘courtesan’, oh aren’t we grand. Harlot’s not good enough for us eh? Paramour, concubine, fille de joie. That’s what we are not. Well listen to me my fine fellow, you are a bit of tail, that’s what you are.
Secretary I am not, you demented fictional character.
Biggles Algy says you are. He says you’re no better than you should be.
Maybe the Pythons changed the definition of the expression from what it was before, but this was the first I’d heard of it, and the context makes it clear – loose women, and outright prostitutes have a funny tendency to, at least on rare occasions, demand to be treated with basic human dignity, or better. But other people don’t see it that way. You, loopy brothel inmate, are not better than that, and will accept any treatment, or at least accept being treated like a whore, would seem to be the theme.
My mother used to describe some young women as ‘no better than [she] ought to be’ and she most definitely meant morals. ‘Common’ was another of her favourite disparaging terms, although the word shouldn’t be loaded at all. Are we not all common?
And she used to give me an old fashioned look all the time. Very critical, my mother.
Heh - I didn’t notice that this was a zombie thread. Glad you finally got your answer.
Southern English here, and I’ve heard the phrase often, though its a little dated now.
It was ALWAYS used IME by someone politely softening an outright condemnation of a persons moral character, usually sexual.