'adiaphorous' originates from Greek, specifically the word 'adiaphoros,' where 'a-' meant 'not' and 'diaphoros' meant 'different.'

'adiaphoros' changed from the Greek word 'adiaphoros' and eventually became the modern English word 'adiaphorous.'

Initially, it meant 'indifferent or neutral,' and this meaning has largely remained the same in modern usage.