Working a second paid job alongside your main one, typically in the evening or at night.
No documented coiner. Etymonline dates the 'hold a second job, especially at night' sense to 1957; the older sense, 'commit crimes at night' (1882), refers to the Irish agrarian Moonlighters, so the criminal sense is the earlier one.
// Where it sits
About a third of US adults report needing one for basic household expenses.
What it really means
The word has a second, much darker life that has almost completely vanished from English.
In 19th-century Ireland, during the Land League disputes, a Moonlighter was someone who made night-time attacks on tenant farmers who were not supporting the League. Organised agrarian violence, carried out after dark. The word meant what you did at night when you did not want to be seen — and only later settled into meaning a second shift.
The modern sense keeps the darkness and drops the menace: work done by moonlight, after the day job.
The numbers are the part worth carrying. A 2023 survey found nearly 39% of Americans reported having a side job. Among New Yorkers, 57% said they needed one to make ends meet — and roughly one-third of US adults report needing one for basic household expenses.
Those figures do a specific thing to the surrounding vocabulary. Side hustle frames the second job as ambition: an entrepreneurial extension, a portfolio career, something you chose. Moonlighting frames it as arithmetic. And when a majority of people in a city say they need one, the ambition framing is not describing what is happening. It is rebranding it.
The generational note is also worth correcting. Millennials were labelled the side-hustle generation for a decade. Gen Z has now surpassed them in rates of working side jobs — which suggests the driver was never a generational attitude to work, and was always the relationship between one wage and one cost of living.
The old word was more honest about the conditions. Something happens at night, and there is a reason nobody wants to look at it directly.
Where it comes from
An older and far darker Irish sense exists: a Moonlighter was someone who made night-time attacks on tenant farmers during 19th-century Land League disputes.
Myths & misconceptions
'Moonlighting' always meant a harmless second job.
The 19th-century Irish sense of MOONLIGHTER meant a participant in coordinated night-time attacks on tenant farmers during Land League disputes. Organised agrarian violence, not extra income — same darkness, entirely different activity.
Side jobs are a Millennial phenomenon.
Millennials were labelled the side-hustle generation, but Gen Z has now surpassed them in rates of working side jobs, and roughly one-third of US adults report needing one for basic household expenses.
Compare & contrast
Moonlighting vs hustle culture
Hustle culture frames the second job as ambition. The 2023 numbers frame it as necessity — 57% of New Yorkers reporting they need one to make ends meet is not a story about drive.
| // | Moonlighting | Hustle culture |
|---|---|---|
| Framing | Necessity | Ambition |
| Chosen | Often not | Nominally |
| Measurable | Yes | No |
| Celebrated | Rarely | Constantly |
How it connects
- Hustle Culturethe ideology that renamed this as ambition.
- Bootstrappingwhere the second job sometimes turns into the first one.
Tell it apart
Questions people ask
- What does moonlighting mean?
- Doing paid work in addition to a main job, usually in the evening or at night.
- Did the word always mean that?
- No. The 19th-century Irish 'Moonlighter' was a night-time agrarian raider during Land League disputes — a completely different and far more violent activity that happened to share the darkness.
- How common are side jobs?
- Nearly 39% of Americans reported one in a 2023 survey, and 57% of New Yorkers said they needed one to make ends meet.