chills and fever vs ague

chills and fever and ague both are nouns.

Word	Noun	Adjective	Verb	Adverb
chills and fever	Yes	No	No	No
ague	Yes	No	No	No

As nouns, chills and fever and ague are synonyms defined as:

chills and fever and ague: successive stages of chills and fever that is a symptom of malaria

chills and fever (noun)	ague (noun)
successive stages of chills and fever that is a symptom of malaria	a mark placed above a vowel to indicate pronunciation
	a fit of shivering or shaking
	successive stages of chills and fever that is a symptom of malaria