staircase wit

Meanings

nounstaircase wit (uncountable)

idiomaticrareuncountableThe thinking of an idea or course of action too late to use it effectively, or the tendency to do so.
When I have completed a manuscript, if I lay it away in a drawer or pigeon-hole, it lies there quietly enough, and my mind seems wholly discharged of it. But if I mail it, I straightaway find myself tormented with "staircase wit" in the shape of emendations.
1887 Jan–Jun, “The Contributors' Club”, in The Atlantic Monthly, volume 59, Atlantic Monthly Co., page 140
2 more examples
So-called Staircase Wit is another example, where we key ourselves up for an important event—an interview, say, or a date—rehearsing how we are going to present ourselves and what we are going to say. Then afterwards we lie awake thinking of all the witty, intelligent, charming things we should have done and said, and didn't because we were so busy trying to remember and revise the plan, […]
1981, Guy Claxton, Wholly Human: Western and Eastern Visions of the Self and Its Perfection, Routledge, page 31
One of the most insightful thinkers I know, the computer entrepreneur Yossi Vardi, prompted me to summarize "my idea" while standing on one leg. It was not too convenient to stand on one leg after a few glasses of perfumed Riesling, so I failed in my improvisation. The next day I experienced staircase wit.
2008, Nassim Nicholas Taleb, The Black Swan: The Impact of the Highly Improbable, Random House, page 131
Synonyms: afterwit, l'esprit de l'escalier, (neologism) retrotort