'hoi' (as an exclamation) originates from Middle English, specifically the word 'hoy', used to call attention; 'hoi' (in the phrase 'hoi polloi') originates from Ancient Greek, specifically the word 'οἱ' (hoi), the plural definite article meaning 'the'.

'hoi' (exclamation) changed from Middle English 'hoy' and later appeared in modern English as 'hoi' for calling attention; separately, 'hoi' in 'hoi polloi' is a direct transliteration of Ancient Greek 'οἱ' and entered English usage through classical references and the preserved Greek phrase.

The exclamation originally and still means 'hey!' or 'attention'; the Greek 'οἱ' originally meant 'the' (plural article), and in the English phrase 'hoi polloi' it retained the sense 'the many' and came to denote 'the common people'.