idiopathic

Idiopathic joins the combining form idio- (from Greek idios, meaning "one's own" or "private") with -pathic, a form that suggests the effects of disease. The combining form idio- is typically found in technical terms. Examples include idiographic, meaning "relating to or dealing with something concrete, individual, or unique"; idiolect, meaning "the language or speech pattern of one individual at a particular period of life"; and idiotype, meaning "the molecular structure and conformation of an antibody that confers its antigenic specificity." A more common idio- word is idiosyncrasy, which most commonly refers to an unusual way in which a person behaves or thinks, or to an unusual part or feature of something.