altitude sickness vs hypoxia

altitude sickness and hypoxia both are nouns.

Word	Noun	Adjective	Verb	Adverb
altitude sickness	Yes	No	No	No
hypoxia	Yes	No	No	No

As nouns, hypoxia is a hypernym of altitude sickness; that is, hypoxia is a word with a broader meaning than altitude sickness:

altitude sickness: effects (as nosebleed or nausea) of oxygen deficiency in the blood and tissues at high altitudes
hypoxia: oxygen deficiency causing a very strong drive to correct the deficiency

altitude sickness (noun)	hypoxia (noun)
effects (as nosebleed or nausea) of oxygen deficiency in the blood and tissues at high altitudes	oxygen deficiency causing a very strong drive to correct the deficiency