a fucking bastard, a motherfucker. About the worst thing you can call someone in Spanish, especially in Mexico.

Loosely it means "son of a bitch." But historically, it meant "son of raped woman." The verb "chingar" comes from a Nahuatl (Aztec) word meaning "to rape." When the Spaniards arrived in the Americas, their raping of the indigenous women was so widespread that chingar began to be used as a curse, similar to the F-word. That is why chingar and its derivatives are not used in Spain but only in Latin American countries, and especially in Mexico.