autumn years vs years

autumn years and years both are nouns.

Word	Noun	Adjective	Verb	Adverb
autumn years	Yes	No	No	No
years	Yes	No	No	No

As nouns, years is a hypernym of autumn years; that is, years is a word with a broader meaning than autumn years:

autumn years: (literary) the later years of one's life, especially after one has finished their career.
years: a late time of life

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

autumn years (noun)	years (noun)
(literary) the later years of one's life, especially after one has finished their career.	a late time of life
	a prolonged period of time
	the time during which someone's life continues