莫名其妙英语怎么说

"莫名其妙" 在英语中可以表达为 "mysterious, inexplicable, or nonsensical". 这个短语源自汉语，可以直接翻译成英文，例如：

This problem is so mysterious. 或者：This problem is so inexplicable. 或者：This problem is so nonsensical.

His actions are always mysterious to me. 或者：His actions are always inexplicable to me. 或者：His actions are always nonsensical to me.

The movie's plot was so mysterious that I didn't understand it at all. 或者：The movie's plot was so inexplicable that I didn't understand it at all. 或者：The movie's plot was so nonsensical that I didn't understand it at all.

不过，需要注意的是，这个短语在英语中并不常见，因此在日常交流中可能不太实用。