A Ched is a derogatory term used mostly by people that are Mexicans themselves that live in places like California or Texas, though not exclusively. It is meant to be significantly more light hearted than terms like Spic, Greaser, Wetback and other slurs.

It refers to someone who is like a Mexican stereotype, but only if the person is not living in Mexico itself. Examples may include someone who Speaks Spanish only or broken English, boot wearer, large hat, watches Futbol/Soccer, and goes to parties where they blast Mexican music.

It's meant to poke fun at Mexicans, usually immigrants and or their kids, who fail to or refuse to assimilate in the US.

It may also be used to describe Mexican music, food, culture. In rare occasions it can refer to a Mexican person in general, regardless of how assimilated that person is.