'flightlessness' originates from the English word 'flightless,' where 'flight' meant 'the act of flying' and '-less' meant 'without.'

'flightless' changed from the Old English word 'flyht' meaning 'flight' and eventually became the modern English word 'flightless.'

Initially, it meant 'without the ability to fly,' and this meaning has largely remained the same in modern usage.