An Etymological Dictionary of the German Language/Annotated/feist

by Friedrich Kluge

feist, adjective, ‘fat, in good condition,’ from Middle High German veiȥt, veiȥet, Old High German feiȥȥit, adjective, ‘fat, greasy’; properly a participle without gi-, ge- of a Gothic verb *faitjan, ‘to fatten,’ Old High German feiȥȥen, which is from the nominal stem faita-, ‘fat,’ Old Icelandic feitr, Middle High German veiȥ. With the assumed Gothic *faitiþs are connected Anglo-Saxon fœ̂ted, fœ̂tt, and English fat (compare fett). Gothic *faita-, from pre-Teutonic paido-, has no unquestionable cognates in the allied languages; it can scarcely be connected with Old Slovenian pitĕti, ‘to nourish, feed,’ on account of the faulty shifting of the dental (Slavonic t corresponding to Gothic t is impossible); it is more probably related to the root πῖδ, ‘to swell, flow forth’; compare πῖδαξ, ‘a spring,’ πιδύω, ‘to gush forth.’