'fairly-decided' originates from the combination of 'fairly' and 'decided', where 'fairly' means 'in a fair manner' and 'decided' means 'determined or resolved'.

'Fairly' comes from Old English 'fægerlice', and 'decided' comes from Latin 'decidere', meaning 'to cut off'.

Initially, 'fairly' meant 'beautifully' in Old English, but evolved to mean 'justly' in modern usage. 'Decided' has largely retained its meaning of 'determined'.