What does "raca" mean in Italian?

Excuse me, could you please clarify the meaning of the word "raca" in the Italian language? I've come across it in a few contexts but I'm not entirely sure of its precise definition or usage. Could you provide some insight into its etymology, any related phrases or idioms, and perhaps some examples of how it might be used in conversation or writing? I'd greatly appreciate your assistance in understanding this term better.