Guiri is one of a number of popular terms in colloquial
European Spanish which denote groups of people not of Spanish origin.
It is perhaps the least offensive of a group including moro, sudaca, bolchevique and arguably gavacho. The term has its origin in Euskera, the
language of the Basque people. It's first recorded use in Spanish was
during the civil wars, or Carlist Wars of the nineteenth century, when
the so-called Carlists, supporters of the pretender to the Spanish
throne, Charles V, used guiri as an insulting term for their opponents.
Currently the correct use and meaning of guiri is
a subject of some debate. While the word is sometimes used as a
catch-all term for foreigners in general or more specifically foreign
tourists in Spain, it is most often used to describe
either Northern Europeans, or people from Anglophone countries (in both
cases generally for people of stereotypically Northern European
appearance). While many Spaniards consider guiri to be at worst a neutral term, with no real negative connotations, it clearly fits into the category of terms listed above- moro, a correct and neutral term in many historical contexts, but in
current usage as applied to any North African or Arab is clearly
frowned upon; sudaca, for South Americans, particularly those with an identifiably non-European appearance, is perhaps the most offensive of all; bolchevique refers to any Russian or Eastern European: its use would not be considered polite in educated company. The odd man out is gavacho,
which while being intentionally disrespectful only applies to the
French, as opposed to a larger, stereotyped macro-national grouping.
Thus while guiri may conjure up largely benign images for the average Spaniard, it lives in an undesirable linguistic neighbourhood.