There are several synonyms for the popular phrase "it's now or never". One synonym is "seize the moment", which means taking advantage of an opportunity immediately before it disappears. Another synonym is "carpe diem", which is Latin for "seize the day". The phrase emphasizes the importance of living in the present and not putting off until tomorrow what can be done today. "Strike while the iron is hot" is another synonym. It means to take advantage of an opportunity when conditions are favorable. Finally, "make hay while the sun shines" is another synonym, meaning to take advantage of good conditions while they last. Regardless of the synonym used, the message remains the same: act now before it's too late.