Epileptic - Vine's Expository Dictionary of New Testament Words
Epileptic
[ 1,,G4583, seleniazo ]lit., to be moon struck" (from selene, "the moon"), is used in the Passive Voice with Active significance, RV, "epileptic," for AV, "lunatick," Matthew 4:24; Matthew 17:15; the corresponding English word is "lunatic." Epilepsy was supposed to be influenced by the moon.