What does the yiddish word cockamaie?

"Cockamamie" is not a Yiddish word. It's an English slang term, likely derived from the phrase "cock and a bull story," which is a nonsensical or fabricated tale.

It means "absurd, ridiculous, or foolish".

While the word isn't Yiddish, its usage in English may have been influenced by the Yiddish word "kokhma", which means "wisdom." This influence is reflected in the fact that "cockamamie" suggests something foolish or lacking in wisdom.