After-wise means "wise afterwards or too late" - or in other words, the perfect term for describing that feeling of knowing exactly what you should have said (or done) after the opportunity to say it (or do it) has passed you by. 

“事后聪明”是指事情过去以后才觉悟，或聪明得太晚，也就是说，在说或做某事的最好时机过去后，自己才知道该如何去说或做。

例句： You are more after-wise rather than wise. 

你这是事后聪明，事前可不聪明。