- She made a killing on the stock market.
- The comedian killed the audience — they were slain with laughter.
Did this meaning develop slowly over time or did some person or institution invert the definition?
Etymonline has an entry for killing:
While its usage to mean "very funny" is partly covered in another question, its usage via idioms like to make a killing to indicate a "large profit" dates back to 1886 (as noted above). The American Heritage Dictionary of Idioms has the following to say about make a killing:
The Online Etymology dictionary states:
Since the basic meaning of killing is "an act of causing death" I don't think either are surprising slang derivations.
You can either "kill people with laughter" (stop it, you're killing me!) or vanquish your foes in the financial realm (I'm making a killing in the stock market.)
The Dictionary of American Slang Third Edition (1995) says that kill was used to mean "To make an audience helpless with laughter" by 1856. Comedy has a number of violent expressions associated with it, involving metaphorical injury to the audience—"knock them in the aisles," "knock them dead," and "fracture," for example.
I have read that many stand-up comedians, in particular, have mixed feelings about the audience they face, much as a lion tamer might in facing a cage full of lions, and that viewing a successful performance as an exercise in dominance is common. But any performer must have at least some uneasiness at the awareness that the audience's reaction is never certain in advance. And winning their approval is in some sense a matter of defeating their potential disapproval, which threatens the performer.
I doubt that anyone goes to a performance thinking "I sure hope I get killed." But I have heard approving spectators say of favored performers, "They killed tonight," as though the play (or the playlist), and not the audience, were the beautiful victim.
"Kill" has the connotations of to "totally dominate" or "destroy" something.
If you have "killed" someone in the usual sense of the word, they are totally helpless, can't do anything to you, because they are dead.
But you can figuratively "kill" (destroy) someone, by driving them into uncontrollable laughter. Or "kill" a stock market by making a large amount (relative to your investment).
This is an application of "reverse psychology," where a word that is originally bad, can be treated as "very good." Other examples are "awesome" or "bestial."