moron
n. countable C1 Advanced US //ˈmɔˌɹɑn// UK //mˈɔːɹɒn// mo·ron
n. a very stupid person. It is a rude and insulting word to use when you are angry with someone's choices or behavior.
n. a person of low intelligence. Historically used as a clinical term in psychology, it is now considered highly offensive and informal.
He felt like a moron after locking his keys in the car.
The driver shouted at the man who cut him off, calling him a moron for ignoring the red light.
Coined by American psychologist Henry H. Goddard in 1910, from Ancient Greek μωρόν (mōrón), the neuter form of μωρός (mōrós, “foolish, dull”). Coined in the third sense by philosopher Ronald Dworkin.
Usage
Primarily used as a derogatory insult; the historical psychological sense is obsolete and offensive.