Please help me with these. What is the difference between cretino, idiota? Thank you in advance.
Cretino and idiota are analogous to their English cognates "cretin" and "idiot" - words which originated as medical terms for people with various cognitive disabilities, which by extension gained pejorative senses as general insults attacking a person's intelligence.
As derogatory senses are acquired, new technical terms are coined to replace them and/or refer to more specific conditions e.g. moron, imbecile, cretin, idiot, [mentally] retarded, special [needs], autistic.
As a result, older words tend to be less offensive as they lose their original association (and may sound dated). Notable exceptions are terms intersecting with other offensive word classes (e.g. racism in "mongoloid" / mongólico).