What is another word for warning?

Here are some synonyms for "warning," depending on the context:

Formal:

* Alert

* Caution

* Admonition

* Notification

* Premonition

* Forewarning

* Intimation

* Hint

* Notice

Informal:

* Heads-up

* Tip-off

* Heads-up

* Buzz

* Red flag

* Look out

More specific:

* Threat (if the warning is of potential danger)

* Prophecy (if the warning is of something that is likely to happen in the future)

* Alert (if the warning is about an imminent danger)

The best synonym to use will depend on the specific situation and the tone you want to convey.