Definition
Used to describe someone behaving in an extremely strange, foolish, or irrational way, suggesting they have lost their sanity.
精神失常，行为怪异，甚至近乎疯狂。
He must be off his rocker to think about swimming in the winter.
他一定是疯了才会想在冬天游泳。
She said she was quitting her stable job to follow her dreams, you might think she's off her rocker.
她说要辞去稳定的工作去追求梦想，你可能会觉得她疯了。
You're going to eat soup with a fork? You must be off your rocker!
你要用叉子喝汤？你一定是疯了！