'non-aqueousness' originates from the English prefix 'non-' (from Latin 'non' meaning 'not') combined with 'aqueous' which comes from Latin 'aqua' meaning 'water', plus the noun-forming suffix '-ness'.

'non-aqueousness' was formed in modern English by attaching the prefix 'non-' to the adjective 'aqueous' (via Middle English/Old French forms from Latin 'aqua') and then adding the suffix '-ness' to create the noun meaning 'the state of not being aqueous'.

Initially the elements meant 'not' (non-) and 'relating to water' (aqueous); over time the combined modern form has come to mean specifically 'the state or quality of not containing water (especially of solvents or environments)'.