burning anger: wrath pictured as a fierce, blazing heat, and in the Bible almost always God's.
This word paints anger as heat. It comes from a root that means to grow hot or to burn, and it names not just that someone is angry but that the anger blazes. English Bibles reach for phrases like fierce anger, burning anger, or hot displeasure to catch that intensity.
Almost every time it appears, the anger is God's. It usually stands in a set phrase that pictures anger flaring in the face, so the whole expression means something like the heat of his anger. Writers speak of this burning anger being kindled, poured out, sent, carried out, or, again and again, turned away when people repent.
So the word is less about a settled mood than about anger at full heat, the moment when judgment is ready to fall. The prophets use it for the day when God finally acts against sin. The narratives use it for a blaze that repentance can still cool, as when Jonah hopes God will turn from his fierce anger and spare Nineveh.