'painlessness' originates from English, specifically formed from the adjective 'painless' plus the noun-forming suffix '-ness', where 'pain' meant 'suffering' or 'physical hurt' and the suffix '-less' meant 'without'.

'pain' comes from Old French 'peine' (from Latin 'poena' meaning 'penalty, punishment'), which in Middle English became 'pain' with the sense of physical suffering; 'painless' (pain + -less) developed in English to mean 'without pain', and the abstract noun 'painlessness' was formed by adding '-ness'.

Initially, roots related to 'poena' focused on penalty or punishment and later shifted toward physical suffering ('pain'); 'painlessness' has retained the core idea of 'without pain' but later acquired figurative uses meaning 'without difficulty' or 'smoothness'.