'defendant' originates from Latin, specifically the word 'defendere' (to ward off, defend), where 'de-' was a prefix and 'fendere' meant 'to strike/drive off'.

'defendant' changed from the Medieval/Old French form 'defendant' (present participle meaning 'one who defends') into Middle English and eventually became the modern English word 'defendant'.

Initially it meant 'one who defends'; over time in legal usage it came to mean 'the person required to defend themselves in a lawsuit' (i.e., the accused party).