If someone has taken leave of his or her senses it means that he or she is irrational. It may be permanent or it may be temporary, but make no bones about it, the person has definitely lost his or her ability to make sound judgments.
Those who remember the Batman series from the 1960s starring Adam West a Batman and Burt Ward as Robin were reminded that even evil has its standards. In the two-part episode “The Puzzles Are Coming” a shocked Puzzler exclaims at one point:
Have you taken leave of your senses?! I may be an Arch Villain, but I’m an American Arch Villain.
As a side note, the Puzzler was originally an adversary of Superman in the 1940’s comics. The Batman series of the 1960s added the Puzzler when an episode originally written for the Riddler could not be filmed because the actor, Frank Gorshin, was unavailable at the time. Rather than recast the Riddler, the producers introduced the Puzzler.
French author Alphonse Daudet (1840-1897) published his novel “The Immortal” in 1888. In Chapter 15, the following dialogue is found:
“So you are going to be married,” said his father, whose suspicions increased. “And who is the lady?”
“The Duchess Padovani.”
“You must have taken leave of your senses! Why she is five-and-twenty years older than you, and besides–and besides–‘ He hesitated, trying to find a respectful phrase, but at last blurted right out, ‘You can’t marry a woman who to every one’s knowledge has belonged to another for years.”
Twenty years earlier, on January 14, 1868 in the Hawke’s Bay (NZ) Herald, a series of jokes were published. One of them had to do with the naming of a newborn child and the registrar who had duly noted the babe’s name in accordance with the father’s wishes. In the story, the very next day, the wife of the proud father burst into the registrar’s room and the joke continues thusly:
“Fat the mischief has that havrin gomeril o’ a man o’ mine been doin’? Duncan, he says he ca’d the bairn. Oh! but I’ll Duncan him!”
“What is the matter, my good woman? Have you taken leave of your senses?” asked the astonished listener.
“Leave o’ my senses — the bairn’s a lassie — confound you an’ my man thegither; but just waite, he’s got something this mornin’ and I’ll take good care he’ll get something mair gin I was yince hame.”
I won’t spoil the punch line but suffice it to say, the imaginary poor woman’s imaginary husband undoubtedly never forgot the imaginary lesson!
Idiomation was unable to find an earlier published version of this phrase however that it is found in a published joke indicates that it was in use by the general population in 1868 and therefore, it is reasonable to believe it originated with the previous generation.
Historically Speaking 