It means "it's now or never", emphasizing the urgency of the situation. It suggests that an opportunity is present and must be seized immediately, or it will be lost forever.
Here's a breakdown of the meaning:
* Ahora: Now
* Es: It is
* O: Or
* Nunca: Never
Example:
* "Tienes que tomar una decisión ahora, ahora es o nunca."
* (You have to make a decision now, it's now or never.)
This phrase is often used in situations where there is a deadline, a limited time offer, or a special opportunity that needs to be taken advantage of immediately.