From the 1920s until the 1970s, the United States government sterilised tens of thousands in an attempt to “cleanse” US society of “defective genes”. This was eugenics. At the time, American scientists thought imbecility was a genetic trait. In 1924, Virginia enacted a forced sterilisation law to rid society of imbecility and epilepsy. The 1927 case of Buck versus Bell was an attempt to set a precedent for that statute, at least in regard to the former.
In this world of eugenics and forced sterilisation, it was the American eugenicist Dr. Henry H. Goddard who coined the English word “moron”, a term denoting an adult with a mental age of about 8-10. If you look up the definition of the word “moron” in an Oxford English dictionary, you will see that it originates early twentieth century, that it is a scientific or medical term, and that it derives from the Greek word “moros”.
In Matthew 5:22, according to Strong’s, the word “fool” in Greek is μωρός (transliteration “moros”).
“But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.”
– Matthew 5:22
Dr. Henry H. Goddard could have chosen any word for his taxonomy. He could have even made up a brand new word. But, no, he chose to coin an English word using a specific Greek word that Matthew 5:22 mentions. The gist of Matthew 5:22 is that one should not call one’s brethren worthless, or something like that. That would be bad enough. But here Dr. Henry H. Goddard is coining a word for the field of eugenics, for the purpose of ridding society of “defects”.