infant mortality vs mortality

infant mortality and mortality both are nouns.

Word	Noun	Adjective	Verb	Adverb
infant mortality	Yes	No	No	No
mortality	Yes	No	No	No

As nouns, mortality is a hypernym of infant mortality; that is, mortality is a word with a broader meaning than infant mortality:

infant mortality: the death rate during the first year of life
mortality: the ratio of deaths in an area to the population of that area; expressed per 1000 per year

Other hypernyms of infant mortality include death rate, deathrate, fatality rate, mortality rate.

infant mortality (noun)	mortality (noun)
the death rate during the first year of life	the quality or state of being mortal
	the ratio of deaths in an area to the population of that area; expressed per 1000 per year