An Etymological Dictionary of the German Language/Annotated/scheißen
scheißen, verb, ‘to go to stool, excrete,’ from Middle High German schîȥen, Old High German scîȥan; corresponding to the equivalent Dutch schijten, Anglo-Saxon sčîtan, English to shit, Old Icelandic skíta. The common Teutonic root skī̆t, ‘to excrete,’ is probably connected with the Aryan skhī̆d, discussed under scheiden; its literally meaning is perhaps ‘to dissever’?. From the Teutonic cognates are derived Italian (dialectic) scito, ‘excrement,’ and Old French eschiter.