A perfect witty remark, retort, or rejoinder that occurs to one after the fact or too late to be used. I was on the bus home long after being tongue-lashed by my boss when I thought of the perfect things to say that would take him down a few pegs. Ah, this staircase wit, it always comes to me when I can do nothing about it!
See also: wit
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.