senescence vs oldness

senescence and oldness both are nouns.

Word	Noun	Adjective	Verb	Adverb
senescence	Yes	No	No	No
oldness	Yes	No	No	No

As nouns, oldness is a hypernym of senescence; that is, oldness is a word with a broader meaning than senescence:

senescence (noun)	oldness (noun)
the property characteristic of old age	the quality of being old; the opposite of newness
the organic process of growing older and showing the effects of increasing age	the opposite of youngness