T.I. on Also called within-subjects variable. within-subjects variance see within-groups variance. witigo (witiko; wittigo) n. see windigo psychosis. Wittmaack-Ekbom syndrome see ekbom’s syndrome. [Theodor Wittmaack (1817-1873), German physician; Karl-Axel Ekbom (1907-1977), Swedish physician Witzelsucht n. a type of joking mania (German: compulsive wisecracking) that is characterized by a morbid desire to tell poor jokes and meaningless stories and that can be a symptom of damage to the frontal lobe of the brain. T.I. 2016.