Read the excerpt below:

"While the origins of Maya culture remain murky, it's thought to have first emerged between 7000 B.C. and 2000 B.C., when hunter-gatherers abandoned their nomadic habits and created more permanent settlements. Recent analyses suggest that those first settlers came from South America and likely developed their staple food, maize, by 4000 B.C. Maize cultivation dramatically changed the Maya's trajectory, literally fueling the explosion of their society and culture."

Source: https://www.nationalgeographic. com/history/article/who-were-the-maya

Considering the context, the word "murky" can be translated as: