feistyyoudaoicibaDictYouDict[feisty 词源字典]
feisty: [19] Feisty, nowadays a colloquial Americanism for ‘quarrelsome’ or ‘spirited’, originated in Middle English as a term for a ‘farting dog’. It goes back to the now obsolete English verb fist ‘fart’, which came ultimately from Indo-European *pezd- (source also of Latin pēdere ‘break wind’, whence English petard ‘small bomb’ [16], as in ‘hoist with one’s own petard’); like *perd-, the Indo-European ancestor of English fart, this was probably of imitative origin.

In the 16th and 17th centuries the expression fisting dog, literally ‘farting dog’, was applied contemptuously to a ‘mongrel’ or ‘cur’. This eventually became shortened to feist, and (mongrels being notoriously combative) feisty was born.
=> fizzle, petard[feisty etymology, feisty origin, 英语词源]
feisty (adj.)youdaoicibaDictYouDict
1896, "aggressive, exuberant, touchy," American English, with -y (2) + feist "small dog," earlier fice, fist (American English, 1805); short for fysting curre "stinking cur," attested from 1520s, with present participle of now-obsolete Middle English fysten, fisten "break wind" (mid-15c.), from Proto-Germanic *fistiz "a fart," said to be from PIE *pezd- (see fart), but there are difficulties.

The 1811 slang dictionary defines fice as "a small windy escape backwards, more obvious to the nose than ears; frequently by old ladies charged on their lap-dogs." Compare also Danish fise "to blow, to fart," and obsolete English aske-fise, "fire-tender," literally "ash-blower" (early 15c.), from an unrecorded Norse source, used in Middle English for a kind of bellows, but originally "a term of reproach among northern nations for an unwarlike fellow who stayed at home in the chimney corner" [OED].