A derogatory term used to describe Mexicans who have immigrated illegally to the United States by swimming or wading across the Rio Grande--the river that separates the U.S. from Mexico. U.S. Border Patrol began using the word in 1944 to refer to illegal Mexican immigrants who were easily identifiable by their wet clothing. Today the term "wetback" is often used to express animosity towards Central American or Latin American immigrants--legal and illegal--who do not speak English. Meanwhile, in an attempt to reclaim the word, some Mexican-Americans call themselves Los Mojados, meaning "the wet ones."
Cindy: "Hey, have you heard that Rosa's parents came to Florida illegally???"
Mindy: "Yeah... total wetbacks. God, why can't they just go back to Mexico??? They don't belong here."