caused by or evidencing a mentally disturbed condition; "a pathological liar"; "a pathological urge to succeed" of or relating to the practice of pathology; "pathological laboratory
caused by or altered by or manifesting disease or pathology; "diseased tonsils"; "a morbid growth"; "pathologic tissue"; "pathological bodily processes"
You describe a person or their behaviour as pathological when they behave in an extreme and unacceptable way, and have very powerful feelings which they cannot control. He's a pathological liar. a pathological fear of snakes
The study of the microscopic structure of living tissue (histology) of diseased tissue (as opposed to normal histology which studies the histology of healthy tissues)
caused by or altered by or manifesting disease or pathology; "diseased tonsils"; "a morbid growth"; "pathologic tissue"; "pathological bodily processes"