word usage - What's the difference between nauseous and nauseated?

I read an article about the difference between nauseous and nauseated:

It seems the article at last indicate that both nauseous and nauseated can mean the state of wanting to vomit. Is that true? Is that a mistake that too many people make so people basically accept this misusage as correct one?

Answer

Nausea, by itself, is the urge to vomit.

I had really bad nausea.

Nauseated is the verb meaning to become affected with nausea.

I felt really nauseated all of a sudden.

Nauseating is the quality of inflicting nausea on someone.

Man, that smell was really nauseating.

Nauseous is the weird one, which can mean either 'nauseated' or 'nauseating'. Some folks definitely believe that its only proper use is 'nauseating', but Merriam Webster's usage notes disagree:

Those who insist that nauseous can properly be used only in sense 1 ["causing nausea or disgust : NAUSEATING"] and that in sense 2 ["affected with nausea or disgust"] it is an error for nauseated are mistaken. Current evidence shows these facts: nauseous is most frequently used to mean physically affected with nausea, usu. after a linking verb such as feel or become; figurative use is quite a bit less frequent. Use of nauseous in sense 1 is much more often figurative than literal, and this use appears to be losing ground to nauseating. Nauseated is used more widely than nauseous in sense 2.