'contrariness' originates from Latin, specifically the word 'contrarius', where 'contra' meant 'against' and '-arius' meant 'pertaining to'; the English noun was formed by adding the suffix '-ness' to the adjective 'contrary'.

'contrariness' evolved from Middle English 'contrarie' (from Old French 'contraire'), which in turn comes from Latin 'contrarius'; the adjective 'contrary' developed in Middle English and the noun 'contrariness' was later formed by adding the noun-forming suffix '-ness'.

Initially, the root meant 'against' or 'opposite'; over time this developed into meanings of 'opposition' and 'perverse disposition', which are reflected in the modern noun 'contrariness'.