Stranger
late Middle English: shortening of Old French estrangier, from Latin extraneus (see strange).
wiktionary
From Middle English straunger, from Old French estrangier(“foreign, alien”), from estrange, from Latin extraneus(“foreign, external”) (whence also English estrange), from extra(“outside of”). Displaced native Old English fremde. Cognate with French étranger(“foreigner, stranger”) and Spanish extranjero(“foreigner”).
etymonline
stranger (n.)
late 14c., "unknown person, foreigner," from strange + -er (1) or else from Old French estrangier "foreigner" (Modern French étranger), from estrange. Latin used the adjective extraneus as a noun to mean "stranger." The English noun never picked up the secondary sense of the adjective. As a form of address to an unknown person, it is recorded from 1817, American English rural colloquial. Meaning "one who has stopped visiting" is recorded from 1520s.
