without doing; instead of doing
Negative adverbial form related to する: used after verbal nouns as ～せずに, as in 確認せずに, or by itself to mean 'without doing so.' It is a little more formal or written-sounding than しないで.
I sent the email without checking it.
He left the room without replying.
He submitted the documents without checking them.
She sat there all day without doing anything.