The Collaborative International Dictionary
Idiopathic \Id`i*o*path"ic\, Idiopathical \Id`i*o*path"ic*al\, a. [Cf. F. idiopathique.] (Med.) Pertaining to idiopathy; characterizing a disease arising primarily, and not in consequence of some other disease or injury; -- opposed to symptomatic, sympathetic, and traumatic. -- Id`i*o*path"ic*al*ly, adv.
Wiktionary
a. (context pathology English) Of, relating to, or designating a disease or condition having no known cause.
WordNet
adj. (of diseases) arising from an unknown cause; "idiopathic epilepsy"
Usage examples of "idiopathic".
Wren collapsed she was experiencing a complex partial idiopathic seizure as she was clearly unable to respond to exogenous stimuli.
Frock is referring to diffuse idiopathic skeletal hyperostosis, a type of severe degenerative arthritis.
A knowledge of this fact should suggest the probable usefulness of the said Primula, when made into a tincture, and given in small diluted doses thereof, to act curatively for such an eruption if attacking the sufferer from idiopathic causes.
The response was to define them as a new condition designated Idiopathic CD4+ Lymphocytopenia, or ICL, which is obscurese for "unexplained AIDS symptoms.