Anounymous illustration from Jonnathan Swift, Gulliver's travel, The air floating island laputa. Swift had used the Spanish slang word for "whore" ("la puta") as the name of the original castle in the sky. The people in Swift's Laputa were absent-minded technologists who oppressed the lands below them by cutting off the sunlight to them. In that sense Swift's choice of the name does not make any sense, and I have not been able to find anything which explains why he chose that particular name.