'unexpectedly-acquired' is a compound word formed from 'unexpectedly' and 'acquired'. 'Unexpectedly' originates from the Latin word 'exspectare', meaning 'to look out for', with the prefix 'un-' indicating 'not'. 'Acquired' comes from the Latin 'acquirere', meaning 'to seek in addition'.

'Unexpectedly' evolved from the Old French 'expecter', while 'acquired' transitioned from the Old French 'acquerre'.

Initially, 'unexpectedly' meant 'not looked for', and 'acquired' meant 'to gain'. Together, they convey the idea of gaining something without prior anticipation.