idiopathy

noun, plural id·i·op·a·thies.

1. a disease not preceded or occasioned by any known morbid condition.

noun plural -thies

1. any disease of unknown cause

n.

1640s, Modern Latin, from Greek idiopatheia, from comb. form of idios “one’s own” (see idiom) + -patheia, comb. form of pathos “suffering, disease, feeling” (see pathos). Related: idiopathic.

n.

1. A disease of unknown origin or cause.
2. A primary disease arising spontaneously with no apparent external cause.