senility vs geezerhood

senility and geezerhood both are nouns.

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

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

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

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

senility (noun)	geezerhood (noun)
the state of being senile	a late time of life
mental infirmity as a consequence of old age; sometimes shown by foolish infatuations