one of the Old Testament people of coastal Palestine who made war on the Israelites, early 14c., from Old French Philistin, from Late Latin Philistinus, from Late Greek Philistinoi (plural), from Hebrew P'lishtim, "people of P'lesheth" ("Philistia"); compare Akkadian Palastu, Egyptian Palusata; the word probably is the people's name for themselves. Hence, "a heathen enemy, an unfeeling foe" (c. 1600).
"person felt by the writer or speaker to be deficient in liberal culture," 1827, originally in Carlyle, popularized by him and Matthew Arnold, from German Philister "enemy of God's word," literally "Philistine," inhabitants of a Biblical land, neighbors (and enemies) of Israel (see Philistine).
Popularized in German student slang (supposedly first at Jena, late 17c.) as a contemptuous term for "townies," and hence, by extension, "any uncultured person." Philistine had been used in a humorous figurative sense of "an unfeeling enemy" in English from c. 1600. Related: Philistinism.
The people who believe most that our greatness and welfare are proved by our being very rich, and who most give their lives and thoughts to becoming rich, are just the very people whom we call Philistines. [Matthew Arnold, "Sweetness and Light," 1869]