a coherent group of tested general propositions, commonly regarded as correct, that can be used as principles of explanation and prediction for a class of phenomena: Einstein's theory of relativity. Synonyms: principle, law, doctrine.
You can add over- to an adjective or verb to indicate that a quality exists or an action is done to too great an extent. For example, if you say that someone is being over-cautious, you mean that they are being too cautious.
