<<{tsuwm being, I have come to discover, a Hebrew word meaning to fast}

I would throw out this fwiw: the Yiddish word shmata (or shmatteh (or schmata?)), meaning a rag, hence anything worthless (now worthless... this I know :);

or it could be coincidence... shmoincidence.>>

In reverse order:

I vote schmoincidence. People around her stick "schm" onto almost anything (as a carnie did, recently, "Try your luck, schmuck"). But seriously...

"Schmata" rag, yes. Hence, it is also a derragotory term for the kerchief a woman wears to hide her hair from all men but the one she married.

I don't have a Hebrew dictionary, but the word I remember for "fast" (noun form) is Tainus/Tainut (depending whether you come from Northern Europe or Northern Africa). A "Tsee-um," ( the "u" > or < like that in the ger. "unter") on the other hand, is the small ceremony noting the completion of a portion of the Talmud, for example, or the whole thing (a much bigger event). How is "Tswum" used--outside the law?