'defector' originates from Latin, specifically the word 'defectus,' where 'de-' meant 'away' and 'facere' meant 'to do or make.'

'defectus' transformed into the French word 'défecteur,' and eventually became the modern English word 'defector' through Middle English.

Initially, it meant 'one who fails or is lacking,' but over time it evolved into its current meaning of 'one who abandons allegiance.'