Often, when we mention the etymology of a particular term is unknown, we hear from folks eager to pass along their theories (or the stories they've been told) about how a term came into being. (来源：英语杂志 http://www.EnglishCN.com)

That is exactly the case of the word moonraker. Etymologists are not certain as to how moonraker developed its British sense meaning "simpleton; a stupid fellow," but they are familiar with these various (unsubstantiated) theories sent in by helpful listeners.

One popular tale (which has a number of versions) traces moonraker to a pair of bootleggers who had hidden kegs of moonshine in a canal. When they went to retrieve their contraband under the light of the full moon, they were questioned by the local constable. The bootleggers feigned drunkenness and explained they were raking the moon they saw reflected in the water.

Another tale traces moonraker to the fable of a beautiful girl afraid an axe embedded in the ceiling beam would fall and hurt her unborn children. Her exasperated fianc?declared he wouldn't marry her until he found three people more foolish than she. In his travels, he came across villagers wielding rakes as they attempted to rescue the moon from where it had fallen into the millpond. Satisfied, he returned home and got married.