贵妇人 emphasizes both wealth and status — typical translations are 'noblewoman', 'grande dame', or 'society lady'. In modern usage it can be slightly tongue-in-cheek when applied to a wealthy housewife. The neutral term for any woman is
女士 (nǚshì); for an aristocrat specifically,
贵族女子 (guìzú nǚzǐ) is more formal.
