cockroachyoudaoicibaDictYouDict[cockroach 词源字典]
cockroach: [17] Cockroach is a product of folk etymology, the process by which a ‘foreign’ – sounding is adapted by speakers of a language so as to seem more familiar. In this case the foreign word was Spanish cucaracha. This was evidently too much for 17th-century English tongues, so the first element was transformed into cock and the second to roach (presumably after the freshwater fish of that name). Modern English roach ‘butt of a marijuana cigarette’ [20] is probably an abbreviation of cockroach, but this is not certain.
[cockroach etymology, cockroach origin, 英语词源]
cockroach (n.)youdaoicibaDictYouDict
1620s, folk etymology (as if from cock + roach) of Spanish cucaracha "chafer, beetle," from cuca "kind of caterpillar." Folk etymology also holds that the first element is from caca "excrement."
A certaine India Bug, called by the Spaniards a Cacarootch, the which creeping into Chests they eat and defile with their ill-sented dung [Capt. John Smith, "Virginia," 1624].