* Loopy: This term describes someone who is eccentric or acting in a strange, unpredictable way.
* Lunatic: While somewhat outdated, this word suggests a person who is mentally deranged or insane.
* Loony: This is a more informal and playful version of "lunatic".
* Lackadaisical: This term is less about being crazy and more about being absent-minded or unmotivated. It could be used in a context where someone is acting irrationally due to a lack of focus.
Please keep in mind that some of these words have negative connotations and should be used with caution.