A fanciful notion; an unrealistic or ludicrous concept.

plural of moonshine

(mineralogy) A translucent gemstone, an orthoclase feldspar, that has a pearly lustre.

plural of moonset

(obsolete) Crazy or insane when affected by the phases of the Moon. / (by extension) Showing irrational behaviour, especially of a romantic or sentimental nature.

plural of moonsail

plural of moonsault

(professional wrestling) An attack where the wrestler faces away from the supine opponent and executes a backflip landing on the opponent in a splash/press position but facing towards the elevated position.

Sighting the Moon (generally in an Islamic context, where the visibility of the Moon affects the timing of religious events).

plural of moonstone