bootleg (n.)youdaoicibaDictYouDict[bootleg 词源字典]
"leg of a boot," 1630s, from boot (n.1) + leg (n.). As an adjective in reference to illegal iquor, 1889, American English slang, from the trick of concealing a flask of liquor down the leg of a high boot. Before that the bootleg was the place to secret knives and pistols.[bootleg etymology, bootleg origin, 英语词源]