Even though up and out aren't really opposites, psych up and psych out are opposites. This word looks crazy, but you've probably noticed in this video that the pronunciation isn't too complicated.
Well, climb has a silent b at the end, and knee starts with a silent k. But the word no at the beginning of the sentence is the opposite of yes, so it's spelt n-o.
Climb 以不发音的 b 结尾,knee 以不发音的 k 开头。但是句子开头的 no 是 yes 的反义词,所以它的拼写是 n-o。