The term 'detested person or thing' can be summarized as an ANATHEMA, which is an 8-letter word meaning something that is strongly disliked or loathed. ANATHEMA is derived from the Greek word ἀνάθεμα, meaning 'something dedicated' or 'something devoted'. It is often used to refer to a person or thing that is considered to be cursed or evil. In religious contexts, it is used to refer to someone or something that is considered to be blasphemous or heretical.