Neckar vs Neckar River

Neckar and Neckar River both are nouns.

Word	Noun	Adjective	Verb	Adverb
Neckar	Yes	No	No	No
Neckar River	Yes	No	No	No

As nouns, Neckar and Neckar River are synonyms defined as:

Neckar and Neckar River: a river in Germany; rises in the Black Forest and flows north into the Rhine

Neckar (noun)	Neckar River (noun)
a river in Germany; rises in the Black Forest and flows north into the Rhine	a river in Germany; rises in the Black Forest and flows north into the Rhine