In the comment section, fellow writer Charles Prier asked a good question (which I deleted by accident): What is an apprehensive definition of malapropism? Or did he say what is the origin? So sorry, Charles. I’ll try to answer a question I don’t remember clearly.
When I first became captivated by this “humorous misuse or distortion of a word or phrase”, I heard it was named for a Mrs. Malaprop. But I didn’t know who she was. I have since learned (Mr. Google is wonderful) that Mrs. Malaprop was a character noted for her misuse of words in R.B. Sheridan’s comedy The Rivals. (1775) Thus something said that was so ludicrously wrong it was funny, became known as a malapropism.
Now, I must confess my own recent goof. While working on my novel the other day, I had become a little brain dead but was trying to finish the thought before it went away. When I wrote that someone with head trauma had come to, I couldn’t seem to spell the word consciousness. I tried several options but couldn’t make the red line underneath the word go away. I clicked on spell check and chose a correction. Only later as I edited did I see that my character had regained conscientiousness. Which is not a bad thing, but not what I meant.
These things happen to keep me humble.