1 N-COUNT 女校友 You can refer to a woman who used to be a pupil at a particular school or university as an old girl . 女校友 [British]
2 N-COUNT 老太婆;中年老女人 If you refer to an old or middle-aged woman as an old girl, you are referring to her in a disrespectful way. 老太婆;中年老女人 [British, informal, disapproval]