Source : Webster's Revised Unabridged Dictionary (1913)

Gringo \Grin"go\, n. [Amer. Sp., fr. Sp. gringo gibberish; cf.
   griego Greek, F. grigou wretch.]
   Among Spanish Americans, a foreigner, esp. an Englishman or
   American; -- often used as a term of reproach.

Source : WordNet®

gringo
     n : a Latin American (disparaging) term for foreigners
         (especially Americans and Englishmen)