Here are some synonyms for "avert":
* Prevent
* Avoid
* Thwart
* Forestall
* Head off
* Escape
Here are some examples of how to use "avert" in a sentence:
* The driver slammed on his brakes to avert an accident.
* We must take action to avert a climate crisis.
* She averted her gaze from the gruesome scene.
In short, "avert" suggests actively taking steps to avoid a negative outcome.