noun
old rogue; elderly bon vivant; free-spirited older person
A playful, somewhat humorous term for an older person who lives freely, ignoring social conventions, often with a hint of mischief. Not a clinical or derogatory term.
あの不良老年は、夜な夜なバーに繰り出しているらしい。
That old rogue apparently goes out to bars every night.
彼は不良老年と呼ばれるのをむしろ楽しんでいる。
He rather enjoys being called an elderly bon vivant.
A modern coined term from 不良 (delinquent, unruly) and 老年 (old age), likely influenced by the phrase 不良少年 (juvenile delinquent). The exact origin is uncertain, but it appears in contemporary Japanese as a lighthearted label.