The correct answer to this open question is the following.
one of the earliest attempts to categorize personality traits came from Allport & Odbert (1936), who identified 4,500 terms in the dictionary that related to personality. Later, statistical methods were used to reduce these words to a list of 16 personality traits.
We are talking about the study of human traits by important psychologist Gordon Allport, who found 4,500 words in English, that could make a description of people's traits. What he did in the study (Allport & Odbert -1936), was to make a general classification into three important groups to better understand these concepts. The three categories were Central Traits, Cardinal Traits, and Secondary Traits.