'antipatheticalness' originates from Greek, specifically the word 'antipathetikos', where the prefix 'anti-' meant 'against' and 'pathos' meant 'feeling' or 'suffering'.

'antipatheticalness' developed by English formation: Greek 'antipathetikos' passed into Late Latin/Medieval Latin as 'antipathia' (meaning aversion), the adjective 'antipathetic' was formed in English from these roots, and the noun was later formed in Modern English by adding the suffix '-ness' to 'antipathetical'.

Initially, the root words conveyed 'a feeling of aversion' or 'opposition of feeling'; over time this broadened into the descriptive sense 'being directly opposed or contrary', and ultimately the abstract noun meaning 'the quality of being antipathetical'.