trench mouth vs contagion

trench mouth and contagion both are nouns.

Word	Noun	Adjective	Verb	Adverb
trench mouth	Yes	No	No	No
contagion	Yes	No	No	No

As nouns, contagion is a hypernym of trench mouth; that is, contagion is a word with a broader meaning than trench mouth:

trench mouth: an acute communicable infection of the respiratory tract and mouth marked by ulceration of the mucous membrane
contagion: any disease easily transmitted by contact

Other hypernyms of trench mouth include contagious disease, angina.

trench mouth (noun)	contagion (noun)
an acute communicable infection of the respiratory tract and mouth marked by ulceration of the mucous membrane	the communication of an attitude or emotional state among a number of people
	an incident in which an infectious disease is transmitted
	any disease easily transmitted by contact