old girl

noun

• 1British a former female student of a school or college: one of the college’s most famous old girls
• a former female member of a sports team or company: other old girls of this magazine have done well

• 2 informal, chiefly British an elderly woman: they’re a couple of harmless old girls
• an affectionate form of address to a girl or woman: he said, ‘Don’t worry, old girl’