～ずじまい— Never Got Around To It

• 忙しくて、結局その本は読まずじまいだった。

  Isogashikute, kekkyoku sono hon wa yomazu jimai datta.

  I was busy and ended up never reading that book.

  読む → 読まず + じまい = the reading never happened, with regret

• 彼にお礼を言わずじまいで、後悔している。

  Kare ni orei o iwazu jimai de, koukai shite iru.

  I never got to thank him, and I regret it.

  言う → 言わず + じまい = thanking was left undone

• 旅行の計画は結局実行せずじまいになった。

  Ryokou no keikaku wa kekkyoku jikkou sezu jimai ni natta.

  In the end, the travel plans were never carried out.

  する → せず + じまい (irregular) = the plan ended up unrealized

• ・する becomes せずじまい (irregular).
• ・Almost always carries a tone of regret or disappointment.
• ・Often paired with 結局 (in the end) to stress the missed chance.

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones ～ずじまい is tested against.

• ～気味 — A Touch Of, -ish
• ～げ — A Look of…
• ～というものだ — That's Truly What It Is
• ～どおり(に) — Just As
• ～として／としては — In the Capacity Of
• ながらに／ながらの — Just As It Is / While Remaining
• にかかわる — To Concern / A Matter Of
• ～まみれ — Covered All Over