～ずに

～ずに means “without doing” something. It is made from the verb's ない-stem plus the classical negative ず and the particle に: 言わない → 言わずに (“without saying”).

It means the same as ～ないで, but ～ずに sounds more formal and is more common in writing. One irregular form to memorize: する becomes せずに, not しずに.

Doing one thing without doing another

The clause before ～ずに describes an action that did not happen, while the main clause describes what was done instead, or done in that state.

How to form it

Verb ない-form → replace ない with ずに

• 言う（いう）= to say → 言わずに（いわずに）= without saying
• 食べる（たべる）= to eat → 食べずに（たべずに）= without eating
• する = to do → せずに = without doing (irregular)

Key idea

～ずに is the bookish twin of ～ないで: take the ない-form, swap ない for ずに, and you get “without doing X”. Just remember せずに for する.