It is a word derived from the Hebrew trefah, which means broken, broken, forbidden. Inedible, not allowed. It refers to a non-kosher food for Jews. Not observant of kashrut. Which is not among the foods allowed by the kashrut.
That it is not kosher, that it does not comply with the Jewish precepts for food. It is the word Yiddish 1496; 1512; 1522; 1507; (treif "broken, broken") , from Hebrew 1496; 1456; 1512; 1461; 1508; 1464; 1492; 8206; ( trafá "torn") . There are other transliterations such as "tref" or "traif".