pathological

1. (medicine) Pertaining to pathology.Examples: "But we can no longer regard the mere fact of these diffuse condensations of the lung becoming yellow and caseous as an evidence of their tuberculous nature, especially since the pathological anatomists, and among them Virchow, have shown that formations of the most different kind, having not the slightest connection with tubercule— as, for example, old cancerous masses, lymphatic glands swollen by a hyperplasia of cells, hæmorrhagical infarctions, abscesses, &c.— undergo exactly the same caseous transformation."

2. (medicine) Relating to, amounting to, or caused by a physical or mental disorder.Examples: "Paul Canning's performance as Julian gives the character an emotional center that is not in the script: He is vulnerable without being pathological, needy without being pathetic."Synonyms: pathologic

3. (mathematics) Having properties which are counterintuitive or difficult to handle.

4. (computer science) Having properties that cause unusually bad behaviour, especially regarding correctness or performance.