chaste woman; virtuous woman
A somewhat old-fashioned fixed phrase describing a woman of strict morals, especially regarding sexual conduct. Often used in literary or historical contexts.
She was known in the village as a woman of strict virtue.
The adjectival phrase '身持ちが堅い' (of firm moral character) can apply to anyone, while '身持ちの堅い女' is a noun phrase specifically for a woman.
Composed of 身持ち (conduct, behavior) + の (possessive particle) + 堅い (firm, strict) + 女 (woman). The exact historical origin is uncertain, but it reflects traditional moral expectations.