'ruthlessness' originates from the Old English word 'rūth,' which meant 'pity or compassion,' combined with the suffix '-less' to indicate the absence of that quality.

'rūth' transformed into the Middle English word 'ruth,' and eventually became the modern English word 'ruthless' with the addition of '-less.'

Initially, 'rūth' meant 'pity or compassion,' but with the addition of '-less,' it evolved to mean 'without pity or compassion.'