na-adjective, noun
Refers to moral or sexual purity, often in a formal or literary context. Can describe a person's virtue or an abstract ideal.
彼女は貞潔を重んじる家庭で育った。
She was raised in a family that values chastity.
その小説は貞潔な女性の苦悩を描いている。
The novel depicts the anguish of a chaste woman.
純潔 also means purity or chastity, but is more common and can refer to innocence or cleanliness in a broader sense. 貞潔 is more specifically about sexual virtue and has a more formal, literary tone.
Composed of 貞 (てい, 'chastity, virtue') and 潔 (けつ, 'purity, cleanliness'). The exact historical derivation is uncertain, but the kanji combination directly conveys the meaning of moral or sexual purity.