adj. Of, relating to, or designating a disease or condition having no known cause.
the GNU version of the Collaborative International Dictionary of English
adj. Pertaining to idiopathy; characterizing a disease arising primarily, and not in consequence of some other disease or injury; -- opposed to symptomatic, sympathetic, and traumatic.
The Century Dictionary and Cyclopedia
In pathology, of or pertaining to a primary morbid state; not secondary or arising from any other disease: as, an idiopathic affection: opposed to symptomatic.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. (of diseases) arising from an unknown cause
Word Usage
"The word idiopathic in idiopathic pulmonary fibrosis means no one knows what causes the disease."