Hello Smiler , The direct meaning as a noun is " the light of the moon " . Moonlighting as a verb 它的隐含的意思是： - working at a secondary job ( usually after hours) " The university student is moonlighting as a taxi driver" - It had a specific meaning also in 19th-century Ireland: the carrying out of cattle-maiming, murders, etc., during the night in protest against the land-tenure system.

Moonlighting Work at second job ( 兼職) : to have a second job in addition to a main job

Moonlighting Holding down more than one job (the second is done by moonlight). Usually applied disapprovingly, where the second job has to be performed furtively.