fox (n.)youdaoicibaDictYouDict
Old English fox "a fox," from Proto-Germanic *fuhsaz "fox" (cognates Old Saxon vohs, Middle Dutch and Dutch vos, Old High German fuhs, German Fuchs, Old Norse foa, Gothic fauho), from Proto-Germanic *fuh-, from PIE *puk- "tail" (source also of Sanskrit puccha- "tail").

The bushy tail also inspired words for "fox" in Welsh (llwynog, from llwyn "bush"); Spanish (raposa, from rabo "tail"); and Lithuanian (uodegis, from uodega "tail"). Metaphoric extension to "clever person" was in late Old English. Meaning "sexually attractive woman" is from 1940s; but foxy in this sense is recorded from 1895. A fox-tail was anciently one of the badges of a fool (late 14c.).

A late Old English translation of the Medicina de Quadrupedibus of Sextus Placitus advises, for women "who suffer troubles in their inward places, work for them into a salve a foxes limbs and his grease, with old oil and with tar; apply to the womens places; quickly it healeth the troubles." It also recommends, for sexual intercourse without irritation, "the extremest end of a foxes tail hung upon the arm." Rubbing a fox's testicles on warts was supposed a means to get rid of them.
spoiler (n.)youdaoicibaDictYouDict
1530s, "one who robs or plunders," agent noun from spoil (v.). Meaning "one who mars another's chance at victory" is attested from 1950 in U.S. politics, perhaps from boxing. Aeronautics sense is from 1928, because the flap thwarts the "lift" on the plane; transferred to structures serving a similar purpose on speedboats (1957) and motor vehicles (1963). Meaning "information about the plot of a movie, etc., which might 'spoil' it for one who has not seen it" is attested by 1982.
swart (adj.)youdaoicibaDictYouDict
Old English sweart "black, dark," of night, clouds, also figurative, "wicked, infamous," from Proto-Germanic *swarta- (cognates: Old Frisian, Old Saxon, and Middle Dutch swart, Dutch zwart, Old Norse svartr, German schwarz, Gothic swarts "dark-colored, black"), from PIE root *swordo- "dirty, dark, black" (source of sordid). The true Germanic word, surviving in the Continental languages, displaced in English by black. Of skin color of persons from late 14c. Related: Swartest.
twerp (n.)youdaoicibaDictYouDict
of unknown origin; OED and Barnhart give earliest date as 1925, but the "Dictionary of American Slang" gives a first reference of 1874 (but without citation and I can't find it), which, if correct, would rule out the usual theory that it is from the proper name of T.W. Earp, a student at Oxford c. 1911, who kindled wrath "in the hearts of the rugger-playing stalwarts at Oxford, when he was president of the Union, by being the last, most charming, and wittiest of the 'decadents.' " [Rawson]
"Mean to say you never heard of Sinzy? Why, he's one of the greatest characters in this town. He's a terrible twerp to look at -- got a face like bad news from home, but I guess he's the best jazz piano player in the world." [Julian Street, "Cross-Sections," 1923]
wart (n.)youdaoicibaDictYouDict
Old English weart "wart," from Proto-Germanic *warton- (cognates: Old Norse varta, Old Frisian warte, Dutch wrat, Old High German warza, German warze "wart"), from PIE root *wer- (1) "high, raised spot on the body, or other bodily infirmity" (cognates: Latin verruca "swelling, wart;" see vary). Phrase warts and all "without concealment of blemishes" is attested from 1763, supposedly from Oliver Cromwell's instruction to his portrait painter.