Describes unwavering chastity, typically of a wife toward her husband. Often used in formal or literary contexts.
She is known as a wife of steadfast chastity.
昔の女性には貞操堅固が求められた。
Women in the past were expected to be strictly chaste.
貞操 is the noun 'chastity' or 'virtue,' while 貞操堅固 is the compound adjective/noun meaning 'firmly chaste.'
貞淑 also means 'chaste' or 'virtuous' (especially of a woman), but is a simpler adjective and more common in modern usage.
A yojijukugo (four-character compound) combining 貞操 (chastity) and 堅固 (firm, steadfast). The exact historical derivation is uncertain, but it follows a common pattern of pairing a virtue with a reinforcing adjective.