Moonlight is literally the light we can see shining from the moon, but to moonlight is to work a second job. Get it? You have to work in the moonlight because there aren’t enough hours in the day.
Moonlight is the reflection of the sun off the moon's surface — a clear sky and a full moon provide brilliant moonlight. Smugglers hate moonlight. If you moonlight, you work a second job, and it doesn’t have to be at night. If your history teacher also works as a mascot for a baseball team, he moonlights as a dancing bear. As a verb, it used to mean “commit crimes at night,” but now just means “to work a second job.”