〜ずじまい

1. Origins, structure, and basic meaning

• Structure: Attach じまい to a verb's negative ず form to show that an intended action was never carried out before the opportunity or situation ended.
• Basic usage: 手紙を書こうと思ったが、結局書かずじまいだった。 describes an intention to write a letter that ultimately remained unfulfilled.

2. Common pitfalls and similar expressions

• Negative and negative potential forms
  • 書く becomes 書かずじまい, and する becomes せずじまい. 行けずじまい negates the potential form 行ける, highlighting that going proved impossible.
• Not yet versus an unfulfilled ending
  • まだ書いていない describes the present state of not having written it yet. 書かずじまいだった focuses on the opportunity ending without the writing being done.