senility vs age

senility and age both are nouns.

Word	Noun	Adjective	Verb	Adverb
senility	Yes	No	No	No
age	Yes	No	Yes	No

As nouns, age is a hypernym of senility; that is, age is a word with a broader meaning than senility:

senility: mental infirmity as a consequence of old age; sometimes shown by foolish infatuations
age: a late time of life

Other hypernyms of senility include eld, geezerhood, old age, years.

senility (noun)	age (noun)
the state of being senile	how long something has existed
mental infirmity as a consequence of old age; sometimes shown by foolish infatuations	a time of life (usually defined in years) at which some particular qualification or power arises
	a late time of life
	an era of history having some distinctive feature
	a prolonged period of time