RhymeZone: septuagenary definitions

Definitions of septuagenary:

adjective: (now rare) Of or related to the number seventy, particularly
adjective: Synonym of septuagenarian: lasting or aged seventy years; seventy-year-old.
noun: (now rare) Synonym of septuagenarian: a seventy-year-old.

(Definitions from Wiktionary)