fress: a Yiddish loanword for eating with vigor, whole-heartedly, as explained HERE
treif (TRAYF): Yiddish for foods expressly prohibited under the laws of Kahshrut, including pork and shellfish
kasher: synonym used in Israel and Sephardic venues elsewhere for the Ashkenazi word kosher; the regulations involving foodstuff are quite complex, and in addition to the prohibitions mandate separation of particular allowed sources, e.g. meat and dairy; kashery (noun and adjective) is the author's personal neologism.
It is suggested that those concerned about a particular eatery should consult their spiritual advisor.
Our collection of 'Non-Sequiturs' on our parent blog "Edifying Nonsense", contains an unusual assortment of odds-and-ends, that don't quite fit into other topic-based offerings. But should you want to review the entire collection, click HERE.