The word "Idiopathetic" is a complicated one in terms of spelling. It refers to a disease or condition that arises spontaneously or for which the cause is unknown. The word is pronounced as "ˌɪdiəpəˈθɛtɪk" (ih-dee-uh-puh-thet-ik) in IPA phonetic transcription. The spelling of the word includes the prefix "idi-" meaning one's own or individual, and the suffix "-pathetic" meaning relating to suffering or feeling. The mid-syllable "o" sound is represented by the letter "a" and the final syllable is spelled with "-etic."
Idiopathic.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.