Cretin
Part of speech: noun
Definition: A person who fails to develop mentally and physically due to a congenital deficiency of thyroid hormones. An idiot.
Idiot
Part of speech: noun
Definition: A common term for a person of low general intelligence.A medical or psychological term meaning a person who lacks the capacity to develop beyond the mental age of a normal four-year-old.
Example sentence: I don't mind being criticised, because I am not that easy to knock down, and no-one can destroy me. But I am bothered by the stupid people who call me dirty, brainless, and an idiot. You don't say words like these to someone who you know nothing about.