Idiopathic definitions

Webster's 1828 Dictionary

IDIOPATH'IC, a. [See Idiopathy.] Pertaining to idiopathy; indicating a disease peculiar to a particular part of the body, and not arising from any preceding disease; as idiopathic head-ach. The epilepsy is idiopathic, when it proceeds from some fault in the brain; but sympathetic,when it is the consequence of some other disorder.
The term idiopathic is also applied to general as well as local diseases, as idiopathic fever. It then signifies, not sympathetic or symptomatic, not arising from any previous disease.

WordNet (r) 3.0 (2005)

adj
1: (of diseases) arising from an unknown cause; "idiopathic epilepsy"

Merriam Webster's

adjective Date: 1669 1. arising spontaneously or from an obscure or unknown cause ; primary <idiopathic epilepsy> 2. peculiar to the individual • idiopathically adverb

Webster's 1913 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.