'unexpectedly-steady' is a compound word formed from 'unexpectedly' and 'steady'. 'Unexpectedly' originates from the Latin word 'exspectare', meaning 'to look out for', and 'steady' comes from the Old English 'stede', meaning 'place'.

'Unexpectedly' evolved from the Latin 'exspectare' through Old French 'expecter', while 'steady' evolved from Old English 'stede'.

Initially, 'unexpectedly' meant 'not foreseen', and 'steady' meant 'firmly placed'. Together, they convey a sense of surprising stability.