How do you say nutcase in yiddish?

There isn't a single, direct translation for "nutcase" in Yiddish that perfectly captures the same meaning. However, depending on the context and nuance you want to convey, here are some options:

Informal and humorous:

* Meshugge: This is a very common Yiddish word meaning crazy, eccentric, or foolish. It's often used in a playful or affectionate way.

* Narishkeit: Literally meaning "foolishness", this word implies someone is acting silly or nonsensically.

* Meshugeneh: The feminine form of "Meshugge."

More negative and intense:

* Meshuggener: This is the masculine form of "Meshugeneh" and can be used to describe someone who is completely out of their mind or dangerous.

* Knave: This word implies someone is deceitful and cunning, not just mentally unstable.

* Tzoresmacher: This means "troublemaker" and suggests someone who is constantly causing problems due to their mental state.

More literal and specific:

* Mensch mit a gedanken-shiva: Literally "a person with a thought-fever," this describes someone who is mentally ill and delusional.

Remember that the choice of word depends on the specific context and the tone you want to convey.