11 Mexican Slang Words Only the Locals Know Pendejo. One of the most used slang words in Mexico is calling someone a 'pendejo'. ... Güey. Güey, sometimes spelled in the way it is pronounced as 'wey', means “mate” and is used all the time in Mexican Spanish. ... Chido & Padre. ... Cabrón. ... Buena Onda. ... La Neta. ... Pinche. ... Crudo. More items... Jan 7, 2019