In one of my posts ("commonly used" vs "sound natural" and "is idiomatic") I said
Obviously, idiomatic and natural are synonyms each other.
In my native language, "each other" is for emphasizing in this kind of situation. However, I am not sure whether it conveys that information in English. So, I looked up Cambridge Dictionary, and got this example
The words "small" and "little" are synonyms.
So, is "are synonyms each other" a bit wordy?