Word Phrase: l'esprit de l'escalier
Pronunciation: \e-SPREE des-kal-i-YE\
Etymology: literally, staircase wit in French; in German, the same concept is called treppenwitz.
Date: credited to the French author and encyclopedist Denis Diderot in his Paradoxe sur le Comédien, written between 1773 and 1778 but not published until 1830
Definition: the predicament of thinking of the right comeback too late
I am a big fan of the clever comeback, . . . but, like most, I usually struggle to come up with something witty quickly enough to be effective. Typically, I either suffer from l'esprit de l'escalier . . . or else come up with something less Shakespeare and more Monty Python (e.g., "Your mother was a hamster and your father smelt of elderberries."). So frustrating, but at least universal.