fistyoudaoicibaDictYouDict[fist 词源字典]
fist: [OE] Like finger, fist seems etymologically to be a reference to the number of fingers on the hand. It comes from a prehistoric West Germanic *fūstiz (source also of German faust and Dutch vuist). This may represent an earlier *fungkhstiz, which has been referred to an Indo- European ancestor *pngkstis, a derivative of *pengke ‘five’. (Dutch vuist ‘fist’, incidentally, is probably the source of English foist [16], which originally denoted the dishonest concealing of a dice in one’s hand.)
=> finger, five, foist[fist etymology, fist origin, 英语词源]
fist (n.)youdaoicibaDictYouDict
Old English fyst "fist, clenched hand," from West Germanic *fustiz (cognates: Old Saxon fust, Old High German fust, Old Frisian fest, Middle Dutch vuust, Dutch vuist, German Faust), from Proto-Germanic *funhstiz, probably ultimately from PIE *penkwe- "five" (see five, and compare Old Church Slavonic pesti, Russian piasti "fist").

Meaning "a blow with the fist" is from 1767. Fist-fight "duel with the fists" is from c. 1600. As a verb, Old English had fystlian "to strike with the fist."