This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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n. A person who moonlights.

n. A moonshiner.

n. In Ireland, one of a band that engaged in agrarian outrages by night.

n. A serenader by moonlight.

n. One who works at a second job in addition to his main occupation.

n. A member of one of the organized bands of desperados that carried on a system of agrarian outrages in Ireland.

n. Same as moonshiner.

n. One of a party who go about serenading on moonlight nights.

n. a person who holds a second job (usually after hours)

"Shirtless, with a rag and a scrap of soap, the moonlighter washed his face, running the cloth across his neck to work out any kinks that a corrugated metal floor might put there after a long night."

worker   

moonshiner