respiratory disorder vs respiratory illness

respiratory disorder and respiratory illness both are nouns.

Word	Noun	Adjective	Verb	Adverb
respiratory disorder	Yes	No	No	No
respiratory illness	Yes	No	No	No

As nouns, respiratory disorder and respiratory illness are synonyms defined as:

respiratory disorder and respiratory illness: a disease affecting the respiratory system

Other synonyms of respiratory disorder include respiratory disease.

respiratory disorder (noun)	respiratory illness (noun)
a disease affecting the respiratory system	a disease affecting the respiratory system