dodderer vs oldster

dodderer and oldster both are nouns.

Word	Noun	Adjective	Verb	Adverb
dodderer	Yes	No	No	No
oldster	Yes	No	No	No

As nouns, oldster is a hypernym of dodderer; that is, oldster is a word with a broader meaning than dodderer:

Other hypernyms of dodderer include golden ager, old person, senior citizen.

dodderer (noun)	oldster (noun)
one who dodders from old age and weakness	an elderly person