Is Gringo Pejorative?

You said Gringo is a synonym of American; doesn’t Gringo have a pejorative sense?

Yes and no. Webster does affirm it is often used disparagingly for Americans and Brits. But for the DRAE (Diccionario de la Real Academia Española) gringo refers to a foreigner, especially an English speaker, without a pejorative sense. In some countries, in Ecuador, Bolivia and Honduras, for example, blond nationals are called gringos. According to etymologist Ricardo Soca and his book La fascinante historia de las palabras, in Argentina and Uruguay in the early 20th century it was used for Italian immigrants. More.

Gringo is an alteration of Griego, Spanish for Greek. Up to medieval times, explains Soca, Latin names were expressed with the Greek equivalents. The Catholic Church banned the practice, Greek was soon forgotten, and the expression It’s Greek to me was born. Griego changed to gringo and was used not only for unintelligible language but also for foreigners.

A popular myth circulates the Internet: When Americans invaded Mexico in 1846 wearing green uniforms, Mexicans clamored: Green Go! ¡Fuera verdes!

So, it all comes down to intonation and context. If you are in Latin America and he or she whispers: venga mi gringo (come here, you) you should smile and comply. But if he or she, stone in hand, is crying Gringo Go Home, even though the expression is redundant, run, and preferably in zigzag.