cretin [L18th] Cretin is now a term of abuse, but was originally a medical term for a person physically and mentally handicapped as a result of congenital thyroid deficiency. The word is from French crétin, probably from Swiss French crestin ‘Christian’, used to mean ‘human creature’ but in this context with a compassionate sense of ‘poor fellow’. Thyroid problems were once common in the Alps, where the soil lacks essential iodine.