'fairly-treated' originates from the English word 'fairly,' which means 'in a fair manner,' and 'treated,' which is the past participle of 'treat,' meaning 'to behave towards or deal with in a certain way.'

'fairly' comes from the Old English word 'fægerlice,' meaning 'beautifully' or 'pleasantly,' and 'treated' comes from the Old French word 'traitier,' meaning 'to handle' or 'to deal with.'

Initially, 'fairly' meant 'beautifully,' but over time it evolved to mean 'in a fair manner,' while 'treated' has largely retained its original meaning of 'handled' or 'dealt with.'