After an extensive examination of nauseous/nauseated/nauseating, in both literal and figurative senses, Merriam-Webster's Dictionary of English Usage concludes: "At present, nauseous is most often used as a predicate adjective meaning "nauseated" literally; it has some figurative use as well. Usage writers decry these developments of the last 40 years, but they are now standard in general prose. The older sense of nauseous meaning "nauseating," both literal and figurative, seems to be in decline, replaced by nauseating. Nauseated is usually literal, but is less common that nauseous. Any handbook that tells you that nauseous cannot mean "nauseated" is out of touch with the contemporary language. In current use it seldom means anything else."