That's interesting to me, for I (a non-native speaker) am well familiar with the word 'cagey' from more contemporary movies and books. The dictionaries I check

That's interesting to me, for I (a non-native speaker) am well familiar with the word 'cagey' from more contemporary movies and books. The dictionaries I checked list etymology as unknown, however. I'll see if I can't ask one about the "K.G." hypothesis.