Full Definition of SANCTITY. 1. : holiness of life and character: godliness. 2. a: the quality or state of being holy or sacred: inviolability b plural: sacred objects, obligations, or rights.See sanctity defined for English-language learners. See sanctity defined for kids.ull Definition of SANCTITY. 1. : holiness of life and character: godliness. 2. a: the quality or state of being holy or sacred: inviolability b plural: sacred objects, obligations, or rights. See sanctity defined for English-language learners. See sanctity defined for kids.