foulness vs malodorousness

foulness and malodorousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
foulness	Yes	No	No	No
malodorousness	Yes	No	No	No

As nouns, foulness and malodorousness are synonyms defined as:

foulness and malodorousness: the attribute of having a strong offensive smell

Other synonyms of foulness include fetidness, rankness, stinkiness.

foulness (noun)	malodorousness (noun)
the attribute of having a strong offensive smell	the attribute of having a strong offensive smell
(of weather) the badness of the weather
a state characterized by foul or disgusting dirt and refuse
disgusting wickedness and immorality