Cockroach
early 17th century (as cacaroch ): from Spanish cucaracha . The spelling change was due to association with cock1 and roach2.
wiktionary
From Spanish cucaracha(“woodlouse”), from cuca(“butterfly caterpillars”), of onomatopoeic origin; see also Greek κόκκυξ(kókkux) and Late Latin cucus. Influenced, via folk etymology, by cock and roach. Doublet of cucaracha.
etymonline
cockroach (n.)
popular name of a troublesome, voracious insect genus, 1620s, folk etymology (as if from cock (n.1) + roach; compare cockchafer) of Spanish cucaracha "chafer, beetle," from cuca "kind of caterpillar." Folk etymology also holds that the first element is from caca "excrement," perhaps because of the insect's offensive smell.
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].
