'unbias' originates from the prefix 'un-' meaning 'not' and the word 'bias,' which comes from Old French 'biais,' meaning 'slant or inclination.'

'bias' transformed from the Old French word 'biais' and eventually became the modern English word 'bias.' The prefix 'un-' was added to form 'unbias.'

Initially, 'bias' meant 'slant or inclination,' and 'unbias' evolved to mean 'remove such slant or inclination.'