idiopathy
Concise Oxford English Dictionary © 2008 Oxford University Press:
idiopathy /ˌɪdɪˈɒpəθi/
▶noun (pl. idiopathies) Medicine a disease or condition which arises spontaneously or for which the cause is unknown.
– derivatives
idiopathic adjective.
idiopathic adjective.
– origin C17: from mod. L. idiopathia, from Gk idiopatheia, from idios ‘own’ + -patheia ‘suffering’.
'idiopathy' also found in these Oxford entries:

