What does that mean? All mimsy were the borogroves?
"Frummies" is a slang (sometimes derogatory, although that's not how it was meant here) term for ultra-Orthodox Jews, from the Yiddish word frum (Orthodox) which is in turn derived from the German word (I'm not sure if I'm spelling it right) fromm, meaning "pious."
It's also credited to a 1940's writer but I remember it as a child, the tune and some of the words.
The chorus:`Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.'
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