Synonyms for Olden days:

• adj.

  •past (adjective)
  • old,
  • latter-day,
  • early,
  • one time,
  • over,
  • foregoing,
  • one-time,
  • behind one,
  • ex,
  • previous,
  • ages ago,
  • retired,
  • ancient,
  • latter,
  • long-ago,
  • sometime,
  • gone-by,
  • prior,
  • bygone,
  • late,
  • gone by,
  • Latterday,
  • bypast,
  • recent,
  • way back when,
  • preceding,
  • way back,
  • quondam,
  • ex-.

• adv.

  •formerly (adverb)
  • before,
  • water under the bridge,
  • earlier,
  • erstwhile,
  • heretofore,
  • once,
  • away back,
  • lately,
  • radically,
  • already,
  • back,
  • a while back.

• n.

  •antiquity (noun)
  • days of old,
  • former age,
  • old days,
  • remote time,
  • classical times,
  • ancient times,
  • days of yore,
  • time immemorial,
  • former ages,
  • olden days.
  •history (noun)
  • yesteryear.
  •past (noun)
  • yore,
  • Old lang syne,
  • years ago,
  • days gone by,
  • times past,
  • former times.

• Other synonyms:

  •Other relevant words:
  • ancient history,
  • old times.

Antonyms for Olden days:

• adj.

  • past
    current, present.

• adv.

  • formerly
    future, subsequently, currently, presently.

• n.

  • antiquity
    now.