Where it sits
The axis is not human-versus-machine. It is reviewed-versus-not.
Tell it apart
| Aspect | AI slop | Spam |
|---|---|---|
| Defined by | Generation | Delivery |
| Needs a recipient | No | Usually — not search spam |
| Can be sincere | No | Yes — sincere bulk still counts |
| Defined | 2024 | 1990s |
Spam is usually defined by unsolicited DELIVERY — though Google's spam policies also count bulk pages published on your own site. Slop is defined by careless GENERATION — Merriam-Webster pins it to low-quality AI content made in bulk, so slop posted to your own blog is still slop. Willison's own test is stricter: it also has to be pushed at someone who didn't ask.
What it doesn't mean
Dictionaries define it by provenance and quality, but the line people actually draw turns on CONSENT AND REVIEW. As Simon Willison put it: 'Not all promotional content is spam, and not all AI-generated content is slop.' AI content you reviewed and stand behind isn't slop; a human-written mass mailing arguably is.
He has said explicitly that the term was in use long before, and credits another user for the framing — that slop would become to AI what spam became to email. He gave it a definition rather than a birth.
What it really means
The best thing about this word is that its working definition refuses the obvious criterion.
The obvious criterion is made by a machine. The definition that stuck — set out by Simon Willison on 8 May 2024 — is instead about consent and review: content mindlessly generated and thrust upon someone who didn't ask for it.
He puts the comparison directly: not all promotional content is spam, and not all AI-generated content is slop.
That distinction does real work. AI-generated text that someone read, checked and stands behind is not slop. A human-written mass mailing that nobody wanted arguably is. The axis is not human versus machine. It is reviewed versus not — whether a person with a reputation put their name between the output and the reader.
Which is why the canonical example is so useful: a machine-written travel guide that recommended a food bank as an attraction. Nothing about that sentence is impossible for a human to write. What is impossible is for a human to write it, read it back, and publish it.
The word itself is old and precisely chosen. Slop has meant scraps fed to animals, and any inferior, weak or unappetising semi-liquid food, for centuries. Note what that implies. Slop is not poison and not waste. It is food — technically nutritious, produced in volume, and served to something whose preferences are not a consideration.
That is the insult, and it is aimed at the publisher rather than the machine.
Slop was named Word of the Year in 2025 by both Merriam-Webster and the American Dialect Society. Willison did not coin it — he says so, and credits an earlier user for the framing that slop would become to AI what spam became to email. What he supplied was the test, which is the part that lasts.
Where it comes from
English — scraps used as food for animals; any inferior, weak or unappetising semi-liquid food
Slop is c. 1400, from Old English -sloppe, 'dung', related to slyppe, 'slime'; 'semi-liquid food' from the 1650s, 'refuse liquid' from 1815. The centuries-old senses carry the exact contempt the new sense borrows. Slop is not poison. It is food, technically, given to something you do not respect.
- 2022
Early uses of 'slop' for AI-generated material appear in reaction to the first wave of AI image generators.
- 8 May 2024
Simon Willison's post defines slop as content mindlessly generated and thrust upon someone who didn't ask for it, citing a machine-written travel guide that recommended a food bank as an attraction.
- 2025
'Slop' is named Word of the Year by both Merriam-Webster and the American Dialect Society.
In real life
- The case Simon Willison cites: an automatically generated travel guide to Ottawa that listed the city's food bank among its tourist attractions — something no one had read before it was published.
- You search for a simple bread recipe and get ten near-identical pages, each opening with three paragraphs about 'the timeless joy of baking' before disagreeing about the oven temperature.
- 'Why is my feed suddenly full of glossy pictures of impossible animals captioned Amazing!?' 'AI slop. Those accounts post a hundred a day.'
Questions
Q01What makes something slop?
Dictionaries define it by provenance and quality: Merriam-Webster, naming slop its 2025 Word of the Year, gives 'digital content of low quality that is produced usually in quantity by means of artificial intelligence'. Simon Willison's working test adds the part that decides most real cases — was it mindlessly generated and pushed at someone who didn't ask for it?
Q02Who coined it?
No definitive coiner. Willison credits an earlier user for the framing and says the term predates his own use; his contribution was the definition.
Q03Why 'slop'?
The word has meant scraps fed to animals, and any inferior semi-liquid food, for centuries. It is not poison — it is food, technically, given to something whose preferences don't matter.
Sources
- AI slop — Wikipedia.
- Simon Willison — 'Slop is the new name for unwanted AI-generated content' (8 May 2024).
- slop (etymology) — Wiktionary.