rough water vs choppiness

rough water and choppiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
rough water	Yes	No	No	No
choppiness	Yes	No	No	No

As nouns, rough water and choppiness are synonyms defined as:

rough water and choppiness: used of the sea during inclement or stormy weather

Other synonyms of rough water include roughness.

rough water (noun)	choppiness (noun)
used of the sea during inclement or stormy weather	used of the sea during inclement or stormy weather