What is the difference between cretino, stupido, imbecille, idiota?
It's not clear to me which ones are related to actual intelligence, vs displayed intelligence, and in general the other connotations.
I do not refer to the insults that do not follow any specific rule, but to the proper meaning.
From Treccani I see imbecille, idiota, stupido, cretino.
It seems to me that imbecille and idiota are the ones that actually refer to reduced mental abilities, with stupido being an intermediate term and cretino the least strong one, referred more to the behaviour.