Which to use
“sly” is an adjective and “STS” is a noun - they look or sound alike but fill different roles in a sentence.
- #47,613
- “sly” frequency rank
- #40,514
- “STS” frequency rank
- 88127
- confusion score
Side-by-Side Comparison
| Feature | sly | STS |
|---|---|---|
| Definition | Matois, malin. | Navette spatiale américaine ayant effectué 135 vols pour l'agence spatiale américaine (NASA) entre le 12 avril 1981 et juillet 2011. |
Where the eye mixes sly and STS
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence. sly (CCV) and STS (CCC) run the same length but a different consonant-vowel pattern - the shape difference is usually the fastest tell.
Why the eye confuses sly with STS
These two trip readers on the page rather than in the ear: sly is \ˈslaɪ\ while STS is \ɛs te ɛs\. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 88127, derived from the frequency rank of both members and their visual similarity.
sly is recorded at frequency rank #47,613, classified as anadj, pronounced \ˈslaɪ\. STS is at rank #40,514, tagged as anoun, pronounced \ɛs te ɛs\.
Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.
With a confusion score of 88127, this pair ranks #7,405 of 440,172 scored French confusable pairs - among the most confusable pairs.
Orthographic DNA of sly vs STS
Shared letters: s. Private to "sly": ly. Private to "STS": t.
"sly" · 3 letters · shape CCV · "STS" · 3 letters · shape CCC
Frequently Asked Questions
Can "sly" and "STS" be used interchangeably?
Which is more common, "sly" or "STS"?
Useful next steps
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "sly" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "STS" - compare definitions side by side with the headword page. Word entry
- This pair ranks #7,405 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "sly" and "STS" also get mixed up with nearby pairs, the highest-scored neighbour is "sly vs suu". Nearby pair
Confusion rank #7,405 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.