pathological

American  

[path-uh-loj-i-kuhl] / ˌpæθ əˈlɒdʒ ɪ kəl /

Also pathologic

adjective

1. of or relating to pathology, or the science or study of diseases and their causes.

   Research into the pathological origins of alcoholism is ongoing.

2. caused by, indicative of, or involving disease.

   Her white blood cell count had fallen to a pathological level.

3. caused by or evidencing a mentally disturbed condition.

   He is a pathological hoarder.

   They show a pathological lack of concern for the suffering of others.

4. dealing with diseases.

   The neurologist kept a pathological casebook from her practice as a source of examples for lectures.

5. Mathematics. designating a phenomenon or object, such as a function, that is logically and correctly defined but has counterintuitive or paradoxical properties.

6. Computers. relating to or producing a failed outcome or one that is contrary to what was intended or expected.

   This is just an example of what happens when the algorithm encounters pathological data.

   A pathological input shouldn't break the algorithm.

---

pathological British  

/ ˌpæθəˈlɒdʒɪkəl /

adjective

1. of or relating to pathology

2. relating to, involving, or caused by disease

3. informal compulsively motivated

   a pathological liar

---

Other Word Forms

• nonpathologic adjective
• nonpathological adjective
• nonpathologically adverb
• pathologically adverb
• postpathologic adjective
• postpathological adjective
• semipathologic adjective
• semipathological adjective
• semipathologically adverb
• unpathological adjective
• unpathologically adverb

Etymology

Origin of pathological

First recorded in 1680–90; from Greek pathologik(ós) ( pathology, -ic ) + -al ¹

Explanation

If something is caused by a physical or mental disease, it is pathological. Someone with a pathological compulsion for cleanliness might scrub the floors for hours every night. Pathological comes from a Greek word, pathologikos, which means “treating of diseases” — pathos means "suffering." Anyone who studies or works with diseases, from their causes to their symptoms, identifies how the disease affects its victims, in other words, its pathological effects. Remember that this is a medical distinction. If a person has, for example, obsessive-compulsive disorder, his or her repetitive actions are pathological.

Example Sentences

This wasn't depression per se, but a condition known as pathological apathy that Patrick describes as feeling like "floating through time" without solid ground.

From BBC • Feb. 11, 2026

Grinch boosters point out that the villain repents and reforms at the end of the story, shedding his pathological hatred of Christmas.

From Los Angeles Times • Dec. 25, 2025

"We already knew the amygdala was involved in anxiety and fear, but now we've identified a specific population of neurons whose imbalanced activity alone is sufficient to trigger pathological behaviors," explains Lerma.

From Science Daily • Nov. 4, 2025

We moderns, Mr. Delbourgo argues, have gone from theories of “demonic possession to accusations of superstition, obsession, sexual neurosis, and pathological greed down to the recent invention of the medical term ‘hoarding disorder.’”

From The Wall Street Journal • Oct. 24, 2025

Moose are large, and essentially insane with an almost pathological hatred of the dogs, the sled, the musher, trees, trains, cars, and everything else as near as I can figure.

From "Woodsong" by Gary Paulsen