、。
She left without saying a word.
Literal
She [topic-は] one-word [emph-も] not-saying [and-て] went-out.
~ないで is the colloquial-leaning 'without doing' form, with the more formal/literary ~ずに covering the same idea in tighter, written prose. 出て行く is a compound verb of motion: 出る ('exit') + 行く ('go') = 'go out and away from the speaker's vantage.' Past 出て行った tells the scene was completed. 一言も + negative is the textbook 'not a single word' frame; the dramatic charge here suggests anger, grief, or quiet resolve.