pathological

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Of or relating to pathology.
• adjective Relating to or caused by disease.
• adjective Of, relating to, or manifesting behavior that is habitual, maladaptive, and compulsive.

from The Century Dictionary.

• Same as pathologic.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Pertaining to pathology.
• adjective Relating to or caused by a physical or mental disorder.
• adjective mathematics Having properties which are counterintuitive or difficult to handle.
• adjective computer science Having properties that cause unusually bad behaviour, especially regarding correctness or performance.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective caused by or evidencing a mentally disturbed condition
• adjective of or relating to the practice of pathology
• adjective caused by or altered by or manifesting disease or pathology