What is Fitnah? What is the ruling on it? Is it backbiting?

The word "fitna" appears in the Quran with several meanings, including: disbelief (kufr) and polytheism (shirk), creating doubt and leading people astray, severe trial and test, tribulation through war, corruption and incitement, sin, killing, harm, and fighting. The rulings concerning "fitna" vary depending on what is intended by it. However, "fitna" does not appear in the Quran with the meaning of backbiting (gheeba), as backbiting is speaking about people in their absence with what they dislike.