What are antonyms of era?

"Era" is a noun that refers to a period of time characterized by particular events or circumstances. It doesn't really have a direct antonym in the same way that words like "hot" and "cold" do. However, depending on the context, you could use words that imply the opposite of what an "era" represents, such as:

* Moment: A very brief period of time.

* Instant: An extremely short period of time.

* Epoch: A specific point in time or a short period of time that marks a significant change.

* Now: The present time.

* Present: The current time.

* Instantaneous: Happening in a single moment.

The best word to use will depend on the specific context and what you are trying to convey.