'unexpectedly-gone' is a compound word formed from 'unexpectedly' and 'gone'. 'Unexpectedly' originates from the Latin word 'exspectare', meaning 'to look out for', and 'gone' is the past participle of 'go', which comes from the Old English 'gān', meaning 'to move' or 'to go'.

'Unexpectedly' evolved from the Latin 'exspectare' through Old French 'expecter', and 'gone' evolved from Old English 'gān'.

Initially, 'unexpectedly' meant 'not looked for', and 'gone' meant 'moved away'. Together, they now mean 'suddenly absent'.