脑袋秀逗 nǎo dài xiǜ dǒu is an interesting Chinese slang that is derived from two different languages: English and Japanese.
In English, people use the term ‘short’ or ‘short-circuit‘ to describe when two wrong end of electrical points connect together and cause error to occur.
The Japanese brought this term into their language and call it ショート shōto, which shares the similar pronunciation with ‘short’.
The Taiwanese then developed the term ショートinto 秀逗 xiǜ dǒu , but widened its areas of application. The word 秀逗 is no longer limited to describe the malfunction of electricity, but rather, the people. 脑袋 has the meaning of ‘brain; head’, 脑袋秀逗 simply means one’s brain is having a short circuit (not working properly).
In mainland China, the term for ‘short-circuit’ is 短路 Duǎn lù, and the phrase similar to 脑袋秀逗 is 大脑短路 Dà Nǎo Duǎn Lù. 大脑 also means ‘brain; head’, it is just cause that 大脑 rhymes better with 短路， while 脑袋 rhymes better with 秀逗, oh well, what can we say, its just languages.