'unreciprocated' originates from the prefix 'un-' meaning 'not' and the verb 'reciprocate', which comes from Latin 'reciprocatus', the past participle of 'reciprocāre', meaning 'to move back and forth'.

'reciprocāre' transformed into the English word 'reciprocate', and with the addition of the prefix 'un-', it became 'unreciprocated'.

Initially, 'reciprocate' meant 'to move back and forth', but over time it evolved to mean 'to return in kind', and 'unreciprocated' means 'not returned in kind'.