'inbreed' originates from Old English, specifically the word 'inbrēdan,' where 'in-' meant 'within' and 'brēdan' meant 'to breed.'

'inbrēdan' transformed into the Middle English word 'inbrede,' and eventually became the modern English word 'inbreed.'

Initially, it meant 'to breed within a group,' and this meaning has largely remained the same in modern usage.