noun
moonless sky
Poetic or literary term for a night or sky without a visible moon. Not an everyday weather word; used in haiku, waka, and descriptive prose.
無月の夜、星だけが輝いていた。
On the moonless night, only the stars were shining.
Compound of 無 (mu, 'without') and 月 (getsu, 'moon'). The reading むげつ follows standard on'yomi. The word is a straightforward Sino-Japanese coinage.