fox (v.)youdaoicibaDictYouDict[fox 词源字典]
1660s, "to delude" (perhaps implied in Old English foxung "fox-like wile, craftiness"), from fox (n.). The same notion is implied in Old English verbal noun foxung "fox-like wile, craftiness;" and Middle English had foxerie "wiliness, trickery, deceit." Foxed in booksellers' catalogues (1847) means "stained with fox-colored marks" (rusty red-brown). In other contexts the past-participle adjective typically meant "drunk" (1610s).[fox etymology, fox origin, 英语词源]
outfox (v.)youdaoicibaDictYouDict
"outwit," 1939, from out + fox (q.v.). Related: Outfoxed; outfoxing.