venereal infection vs contagion

venereal infection and contagion both are nouns.

Word	Noun	Adjective	Verb	Adverb
venereal infection	Yes	No	No	No
contagion	Yes	No	No	No

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

venereal infection: a communicable infection transmitted by sexual intercourse or genital contact
contagion: any disease easily transmitted by contact

Other hypernyms of venereal infection include contagious disease.

venereal infection (noun)	contagion (noun)
a communicable infection transmitted by sexual intercourse or genital contact	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