'pathologic' originates from Modern Latin, specifically the word 'pathologicus', where the element 'patho-' meant 'suffering, disease' and the element '-logic' (from Greek 'logos') meant 'study' or 'reason'.

'pathologic' changed from Ancient Greek 'pathologikos' to Late/Medieval Latin 'pathologicus' and then entered English (via scientific/medical Latin usage) as 'pathologic' (modern English).

Initially, it meant 'relating to the study or description of disease', but over time it also acquired a figurative meaning of 'abnormal' or 'compulsively extreme' in reference to behavior ('pathologic liar', etc.).