unhealthiness vs health problem

unhealthiness and health problem both are nouns.

Word	Noun	Adjective	Verb	Adverb
unhealthiness	Yes	No	No	No
health problem	Yes	No	No	No

As nouns, unhealthiness and health problem are synonyms defined as:

unhealthiness and health problem: a state in which you are unable to function normally and without pain

Other synonyms of unhealthiness include ill health.

unhealthiness (noun)	health problem (noun)
a state in which you are unable to function normally and without pain	a state in which you are unable to function normally and without pain