Good source, an even better source is the very first Mishna in Tractate Sukkah [0] which uses the Hebrew form of the word kosher several times to refer to a Suk

Good source, an even better source is the very first Mishna in Tractate Sukkah [0] which uses the Hebrew form of the word kosher several times to refer to a Sukka. It's used as both an adjective ("כשרה") and a verb ("מכשירין" - using the Aramaic form of pluralization). Interestingly, the opposite of kosher in this mishna is פסול, which I'd translate as "invalid". Also interesting is the apparent relationship between the word כשר and the modern Hebrew מכשיר, meaning "device", or "thing that does something specific". Edit: took me another moment to realize the root is used a lot in modern Hebrew, such as in the word כושר (ironically pronounced like the English kosher), which means (physical) fitness. [0] https://he.m.wikisource.org/wiki/%D7%9E%D7%A9%D7%A0%D7%94_%D7%A1%D7%95%D7%9B%D7%94_%D7%90_%D7%90 https://he.m.wikisource.org/wiki/%D7%9E%D7%A9%D7%A0%D7%94_%D...