'exemptness' ultimately originates from Latin, specifically from the past participle notion derived from 'eximere' (later 'exemptus'), where 'ex-' meant 'out' and 'emere' meant 'take'.

'exemptness' developed via Middle English (Middle English 'exemptnesse') from Old French and Medieval Latin forms based on Latin 'exemptus'; the English adjective 'exempt' preceded the nominal abstract formation 'exemptness'.

Initially related to the literal sense 'taken out' or 'removed' (from obligations or duties); over time it evolved to mean the modern sense 'freedom from obligation or liability'.