'unexpectedly-set' originates from the combination of 'unexpectedly' and 'set', where 'unexpectedly' is derived from 'unexpected', meaning 'not expected', and 'set' meaning 'to place or fix in a position'.

'Unexpectedly' evolved from the Old English 'un-' meaning 'not' and 'expect' from Latin 'expectare', while 'set' comes from Old English 'settan'.

Initially, 'unexpectedly' meant 'not foreseen', and 'set' meant 'to place', which together evolved to mean 'placed without prior notice'.