wetback

[wet-bak]
noun Slang: Extremely Disparaging and Offensive.
  1. a contemptuous term used to refer to a Mexican laborer who enters the U.S. illegally, as by wading the Rio Grande.

Origin of wetback

An Americanism dating back to 1945–50; wet + back1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for wetback

wetback

noun
  1. US informal, offensive a Mexican labourer who enters the US illegally

Word Origin for wetback

C20: illegal immigrants would swim across the Rio Grande river to reach the US
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for wetback
n.

"illegal Mexican immigrant to the U.S.," c.1924, from wet (adj.) + back (n.); from notion of wading the Rio Grande.

Online Etymology Dictionary, © 2010 Douglas Harper