More on "Huachicol"

From Wikipedia:  According to a Mexican expert on the origin of language, Arturo Ortega Moran, the word derives from the Latin word "aquati," which means "watery."  It was used in Europe during the 16th century by artists to refer to diluting pigments with water.  In France this term was spelled "gouache," and during the French occupation of Mexico in the nineteenth century the term was used by artists, as in "painting a la guach."  The term was used subsequently in Mexico to refer to sellers of tequila and cane sugar who added water to the product to stretch profits, as in "guchicolero" or "huachicolero."  In the age of automobiles vendors of gasoline who watered down their product became known as "huachicoleros."  Today, with the sudden rise in stealing gasoline from Pemex, the term has come to mean "those who steal and sell gasoline." 

There is a different version circulating as well.  According to the Diccionario de Mexicanismos, the word derives from the Mayan word "waach," which referred to "outsiders."  This term was translated into Spanish as "guache," or "huache."  Over time the meaning morphed into a term used to describe something of poor quality, or false, and was used especially to refer to people who adulterated tequila or cane liquor.  Today it refers to those who steal and sell gasoline, and is gradually extending to include public corruption, at least as it is sometimes being used in Juárez.