Nefas

The vocabulary of ancient Roman religion was highly specialized. Its study affords important information about the religion, traditions and beliefs of the ancient Romans. This legacy is conspicuous in European cultural history in its influence on later juridical and religious vocabulary in Europe, particularly of the Western Church. This glossary provides explanations of concepts as they were expressed in Latin pertaining to religious practices and beliefs, with links to articles on major topics such as priesthoods, forms of divination, and rituals.

For theonyms, or the names and epithets of gods, see List of Roman deities. For public religious holidays, see Roman festivals. For temples see the List of Ancient Roman temples. Individual landmarks of religious topography in ancient Rome are not included in this list; see Roman temple.

The verb abominari ("to avert an omen", from ab-, "away, off," and ominari, "to pronounce on an omen") was a term of augury for an action that rejects or averts an unfavourable omen indicated by a signum, "sign". The noun is abominatio, from which English "abomination" derives. At the taking of formally solicited auspices (auspicia impetrativa), the observer was required to acknowledge any potentially bad sign occurring within the templum he was observing, regardless of the interpretation. He might, however, take certain actions in order to ignore the signa, including avoiding the sight of them, and interpreting them as favourable. The latter tactic required promptness, wit and skill based on discipline and learning. Thus the omen had no validity apart from the observation of it.

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