'bemoan' originates from Old English, specifically the word 'bemǣnan,' where 'be-' meant 'about' and 'mǣnan' meant 'to moan or lament.'

'bemǣnan' transformed into the Middle English word 'bemoanen,' and eventually became the modern English word 'bemoan.'

Initially, it meant 'to moan about something,' and this meaning has largely remained the same in modern usage.