esprit de l'escalier
Huh, you say? What's with all the French words? English is awesome because it is always changing, absorbing words, phrases and nuances from other languages. Today's word is no exception. An esprit de l'escalier is a witty remark thought of too late, on the way home. In other words, it is the clever comment you wish you had delivered and therefore impressed your friends (or enemies). In French it means "staircase wit." I'm sure we've all experienced this before. As writers, I find we can actually use our late witticisms later on... keeping a stockpile until opportunity strikes in our pages.